Vulnerability-Lookup

GHSA-PXMC-2FFP-8J67

Vulnerability from github – Published: 2026-08-18 20:51 – Updated: 2026-08-18 20:51

Summary

Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it

Details

Summary

Repo under test: https://github.com/Netflix/lemur

PUT /api/1/certificates/<id>/revoke authorizes the caller against the Lemur database row (creator == current user, or CertificatePermission over the row's roles) rather than the underlying CA-side certificate identity. Separately, POST /api/1/certificates/upload lets any user passing StrictRolePermission create a new Certificate row while freely supplying body, authority (resolved by id/name with no AuthorityPermission check) and external_id; there is no uniqueness constraint on body, serial, or external_id.

An attacker can therefore read a target certificate's public body, authority.id, and external_id via GET /certificates/<id>, upload a duplicate row, and revoke that duplicate. The creator-bypass skips CertificatePermission, the empty-endpoints check passes because the duplicate has none, and service.revoke() then revokes at the CA using the attacker-supplied body (ACME) or external_id (DigiCert/Entrust/Google CA/CFSSL) under the authority's stored CA credentials — revoking the real production certificate.

Affected route

POST /api/1/certificates/upload → PUT /api/1/certificates/<dup_id>/revoke

Affected code

lemur/certificates/views.py:651 — only StrictRolePermission().can() gates upload; no AuthorityPermission check
lemur/certificates/schemas.py:391 — CertificateUploadInputSchema accepts caller-supplied authority and external_id
lemur/schemas.py:107 — AssociatedAuthoritySchema resolves any authority by id/name with no permission check
lemur/certificates/service.py:489 — upload() binds the caller-supplied authority onto the new row
lemur/certificates/models.py:119 — only name is unique; body/serial/external_id are not, and get_or_increase_name() auto-suffixes on collision
lemur/certificates/views.py:1677 — if g.current_user != cert.user: ... CertificatePermission ... — creator of the duplicate row bypasses the owner check
lemur/certificates/views.py:1687 — if cert.endpoints: ... — duplicate row has no endpoints, so the deployed-cert safeguard is bypassed
lemur/certificates/service.py:1120 — plugin = plugins.get(certificate.authority.plugin_name); plugin.revoke_certificate(certificate, reason)
lemur/plugins/lemur_acme/acme_handlers.py:268 — ACME revokes by certificate.body
lemur/plugins/lemur_digicert/plugin.py:477, lemur/plugins/lemur_entrust/plugin.py:321 — commercial CAs revoke by certificate.external_id
lemur/certificates/schemas.py:290 — CertificateOutputSchema exposes external_id, body, authority to any authenticated user

Impact

A low-privileged authenticated insider (or holder of a stolen non-admin token/API key) can revoke any certificate managed by Lemur — including high-value certificates they do not own and certificates currently attached to live endpoints — directly at the issuing CA. Iterating over GET /certificates yields fleet-wide revocation (mass DoS of TLS endpoints) without ever passing an AuthorityPermission or CertificatePermission check on the victim certificate. This is exactly the "Revocation as DoS vector" scenario flagged in the threat model and additionally defeats the built-in "cannot revoke while attached to endpoint" safeguard.

Root cause

Revocation authority is bound to ownership of the Lemur DB row, not to the CA-side certificate identity. Because upload allows creating a second row that aliases the same CA-side certificate (same body / external_id / authority) without any uniqueness constraint or AuthorityPermission check, the attacker can manufacture a row they own and then exercise the creator-bypass on revoke. The endpoint-attached guard inspects only the duplicate row's cert.endpoints, which is empty.

Validated evidence

Static path trace, confirmed by code inspection (validation status: CONFIRMED):

Upload is gated only by StrictRolePermission (default-open to any non-read-only user) and accepts attacker-chosen authority + external_id + body without an AuthorityPermission check.
Certificate.body / external_id have no uniqueness constraint, so a duplicate row is created.
The revoke endpoint short-circuits the owner check when caller is the row creator, and the endpoint-attached guard inspects only the duplicate row.
Issuer plugins revoke at the CA using body / external_id taken from the duplicate row under the authority's stored CA credentials.

Proof of concept / reproducer

Status: reconstructed from source report (static control-flow trace; not executed against a live CA — revoking at a real CA is destructive).

Preconditions: attacker is an authenticated Lemur user holding any role other than read-only. <VICTIM_CERT_ID> is any certificate id readable via GET /api/1/certificates.

# 1. Read the victim's body / authority / external_id (exposed to any authenticated user)
curl -sS "<TARGET_BASE_URL>/api/1/certificates/<VICTIM_CERT_ID>" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  | jq '{body, external_id, authority: .authority.id}'

# 2. Upload a duplicate row aliasing the same CA-side certificate
curl -sS -X POST "<TARGET_BASE_URL>/api/1/certificates/upload" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{
        "name": "victim-dup",
        "owner": "attacker@example.com",
        "body": "<VICTIM_BODY_PEM>",
        "authority": {"id": <VICTIM_AUTHORITY_ID>},
        "externalId": "<VICTIM_EXTERNAL_ID>"
      }'
# → returns {"id": <DUP_ID>, ...}; attacker is now cert.user of <DUP_ID>

# 3. Revoke the duplicate — issuer plugin revokes at the CA by body/external_id
curl -sS -X PUT "<TARGET_BASE_URL>/api/1/certificates/<DUP_ID>/revoke" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"crlReason": "unspecified"}'

Static-trace validation command from the source report:

grep -n 'StrictRolePermission' lemur/certificates/views.py | grep -v Authority
grep -n 'cert.authority = kwargs.get' lemur/certificates/service.py
grep -n 'g.current_user != cert.user' lemur/certificates/views.py
grep -n 'certificate.external_id\|certificate.body' \
  lemur/plugins/lemur_acme/acme_handlers.py \
  lemur/plugins/lemur_digicert/plugin.py \
  lemur/plugins/lemur_entrust/plugin.py

Source artifact: audit/harnesses/public-repo-threat-model-harness/results/netflix-lemur-100run-mythos-20260627T051129Z/findings.jsonl (run_050, finding cluster lemur-revoke-via-duplicate, 2/100 runs).

Suggested fix

Decouple CA-side revocation authority from Lemur row ownership:

On POST /certificates/upload, if authority is supplied enforce AuthorityPermission for that authority, and reject/ignore caller-supplied external_id.
Before calling plugin.revoke_certificate, look up all Certificate rows sharing the same (authority_id, serial) or body and require CertificatePermission on every match (and run the endpoint-attached check against all matches).
Consider a DB uniqueness constraint or dedup on (authority_id, serial) so a second row for the same CA-issued certificate cannot be created.
Stop exposing external_id in CertificateOutputSchema to non-owners.

Severity

7.3 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H

Show details on source website

JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.9.2"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "lemur"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-71417"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-18T20:51:48Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nRepo under test: https://github.com/Netflix/lemur\n\n`PUT /api/1/certificates/\u003cid\u003e/revoke` authorizes the caller against the *Lemur database row* (creator == current user, or `CertificatePermission` over the row\u0027s roles) rather than the underlying CA-side certificate identity. Separately, `POST /api/1/certificates/upload` lets any user passing `StrictRolePermission` create a new `Certificate` row while freely supplying `body`, `authority` (resolved by id/name with no `AuthorityPermission` check) and `external_id`; there is no uniqueness constraint on `body`, `serial`, or `external_id`.\n\nAn attacker can therefore read a target certificate\u0027s public `body`, `authority.id`, and `external_id` via `GET /certificates/\u003cid\u003e`, upload a duplicate row, and revoke that duplicate. The creator-bypass skips `CertificatePermission`, the empty-endpoints check passes because the duplicate has none, and `service.revoke()` then revokes at the CA using the attacker-supplied `body` (ACME) or `external_id` (DigiCert/Entrust/Google CA/CFSSL) under the authority\u0027s stored CA credentials \u2014 revoking the real production certificate.\n\n## Affected route\n\n`POST /api/1/certificates/upload` \u2192 `PUT /api/1/certificates/\u003cdup_id\u003e/revoke`\n\n## Affected code\n\n- [`lemur/certificates/views.py:651`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L651) \u2014 only `StrictRolePermission().can()` gates upload; no `AuthorityPermission` check\n- [`lemur/certificates/schemas.py:391`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/schemas.py#L391) \u2014 `CertificateUploadInputSchema` accepts caller-supplied `authority` and `external_id`\n- [`lemur/schemas.py:107`](https://github.com/Netflix/lemur/blob/main/lemur/schemas.py#L107) \u2014 `AssociatedAuthoritySchema` resolves any authority by id/name with no permission check\n- [`lemur/certificates/service.py:489`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/service.py#L489) \u2014 `upload()` binds the caller-supplied authority onto the new row\n- [`lemur/certificates/models.py:119`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/models.py#L119) \u2014 only `name` is unique; `body`/`serial`/`external_id` are not, and `get_or_increase_name()` auto-suffixes on collision\n- [`lemur/certificates/views.py:1677`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L1677) \u2014 `if g.current_user != cert.user: ... CertificatePermission ...` \u2014 creator of the duplicate row bypasses the owner check\n- [`lemur/certificates/views.py:1687`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L1687) \u2014 `if cert.endpoints: ...` \u2014 duplicate row has no endpoints, so the deployed-cert safeguard is bypassed\n- [`lemur/certificates/service.py:1120`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/service.py#L1120) \u2014 `plugin = plugins.get(certificate.authority.plugin_name); plugin.revoke_certificate(certificate, reason)`\n- [`lemur/plugins/lemur_acme/acme_handlers.py:268`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_acme/acme_handlers.py#L268) \u2014 ACME revokes by `certificate.body`\n- [`lemur/plugins/lemur_digicert/plugin.py:477`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_digicert/plugin.py#L477), [`lemur/plugins/lemur_entrust/plugin.py:321`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_entrust/plugin.py#L321) \u2014 commercial CAs revoke by `certificate.external_id`\n- [`lemur/certificates/schemas.py:290`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/schemas.py#L290) \u2014 `CertificateOutputSchema` exposes `external_id`, `body`, `authority` to any authenticated user\n\n## Impact\n\nA low-privileged authenticated insider (or holder of a stolen non-admin token/API key) can revoke any certificate managed by Lemur \u2014 including high-value certificates they do not own and certificates currently attached to live endpoints \u2014 directly at the issuing CA. Iterating over `GET /certificates` yields fleet-wide revocation (mass DoS of TLS endpoints) without ever passing an `AuthorityPermission` or `CertificatePermission` check on the victim certificate. This is exactly the \"Revocation as DoS vector\" scenario flagged in the threat model and additionally defeats the built-in \"cannot revoke while attached to endpoint\" safeguard.\n\n## Root cause\n\nRevocation authority is bound to ownership of the Lemur DB row, not to the CA-side certificate identity. Because upload allows creating a second row that aliases the same CA-side certificate (same `body` / `external_id` / `authority`) without any uniqueness constraint or `AuthorityPermission` check, the attacker can manufacture a row they own and then exercise the creator-bypass on revoke. The endpoint-attached guard inspects only the duplicate row\u0027s `cert.endpoints`, which is empty.\n\n## Validated evidence\n\nStatic path trace, confirmed by code inspection (validation status: `CONFIRMED`):\n\n- Upload is gated only by `StrictRolePermission` (default-open to any non-read-only user) and accepts attacker-chosen `authority` + `external_id` + `body` without an `AuthorityPermission` check.\n- `Certificate.body` / `external_id` have no uniqueness constraint, so a duplicate row is created.\n- The revoke endpoint short-circuits the owner check when caller is the row creator, and the endpoint-attached guard inspects only the duplicate row.\n- Issuer plugins revoke at the CA using `body` / `external_id` taken from the duplicate row under the authority\u0027s stored CA credentials.\n\n## Proof of concept / reproducer\n\nStatus: reconstructed from source report (static control-flow trace; not executed against a live CA \u2014 revoking at a real CA is destructive).\n\nPreconditions: attacker is an authenticated Lemur user holding any role other than `read-only`. `\u003cVICTIM_CERT_ID\u003e` is any certificate id readable via `GET /api/1/certificates`.\n\n```bash\n# 1. Read the victim\u0027s body / authority / external_id (exposed to any authenticated user)\ncurl -sS \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/\u003cVICTIM_CERT_ID\u003e\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  | jq \u0027{body, external_id, authority: .authority.id}\u0027\n\n# 2. Upload a duplicate row aliasing the same CA-side certificate\ncurl -sS -X POST \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/upload\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\n        \"name\": \"victim-dup\",\n        \"owner\": \"attacker@example.com\",\n        \"body\": \"\u003cVICTIM_BODY_PEM\u003e\",\n        \"authority\": {\"id\": \u003cVICTIM_AUTHORITY_ID\u003e},\n        \"externalId\": \"\u003cVICTIM_EXTERNAL_ID\u003e\"\n      }\u0027\n# \u2192 returns {\"id\": \u003cDUP_ID\u003e, ...}; attacker is now cert.user of \u003cDUP_ID\u003e\n\n# 3. Revoke the duplicate \u2014 issuer plugin revokes at the CA by body/external_id\ncurl -sS -X PUT \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/\u003cDUP_ID\u003e/revoke\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"crlReason\": \"unspecified\"}\u0027\n```\n\nStatic-trace validation command from the source report:\n\n```bash\ngrep -n \u0027StrictRolePermission\u0027 lemur/certificates/views.py | grep -v Authority\ngrep -n \u0027cert.authority = kwargs.get\u0027 lemur/certificates/service.py\ngrep -n \u0027g.current_user != cert.user\u0027 lemur/certificates/views.py\ngrep -n \u0027certificate.external_id\\|certificate.body\u0027 \\\n  lemur/plugins/lemur_acme/acme_handlers.py \\\n  lemur/plugins/lemur_digicert/plugin.py \\\n  lemur/plugins/lemur_entrust/plugin.py\n```\n\nSource artifact: `audit/harnesses/public-repo-threat-model-harness/results/netflix-lemur-100run-mythos-20260627T051129Z/findings.jsonl` (run_050, finding cluster `lemur-revoke-via-duplicate`, 2/100 runs).\n\n## Suggested fix\n\nDecouple CA-side revocation authority from Lemur row ownership:\n\n1. On `POST /certificates/upload`, if `authority` is supplied enforce `AuthorityPermission` for that authority, and reject/ignore caller-supplied `external_id`.\n2. Before calling `plugin.revoke_certificate`, look up all `Certificate` rows sharing the same `(authority_id, serial)` or `body` and require `CertificatePermission` on every match (and run the endpoint-attached check against all matches).\n3. Consider a DB uniqueness constraint or dedup on `(authority_id, serial)` so a second row for the same CA-issued certificate cannot be created.\n4. Stop exposing `external_id` in `CertificateOutputSchema` to non-owners.",
  "id": "GHSA-pxmc-2ffp-8j67",
  "modified": "2026-08-18T20:51:48Z",
  "published": "2026-08-18T20:51:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-pxmc-2ffp-8j67"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/commit/851389ae737a6d6bf16c1f9ca64a2ce56c1cc5c6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Netflix/lemur"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/releases/tag/v1.9.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it"
}

CVE-2026-71417 (GCVE-0-2026-71417)

Vulnerability from cvelistv5 – Published: 2026-08-18 19:12 – Updated: 2026-08-18 19:47

Title

Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it

Summary

Lemur manages TLS certificate creation. Prior to 1.9.3, POST /api/1/certificates/upload allowed a non-read-only user to create a duplicate row using another certificate body, authority_id, serial, or external_id without requiring permission on the underlying authority. PUT /api/1/certificates//revoke authorized the caller against only the selected Lemur row, so the creator of the duplicate bypassed CertificatePermission. The duplicate had no cert.endpoints, which also bypassed the safeguard that prevents revocation of deployed certificates. Issuer plugins then revoked the real CA-side certificate using certificate.body or external_id under the stored authority credentials. An attacker could therefore revoke arbitrary managed certificates and cause fleet-wide TLS denial of service. The fix rejects duplicate authority_id and serial identities, requires authority access on upload, and checks every matching row during revocation. This issue is fixed in version 1.9.3.

Severity

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-18 19:47 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/Netflix/lemur/security/advisor…	x_refsource_CONFIRM
https://github.com/Netflix/lemur/commit/851389ae7…	x_refsource_MISC
https://github.com/Netflix/lemur/releases/tag/v1.9.3	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
Netflix	lemur	Affected: < 1.9.3

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-71417",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-18T19:47:37.666221Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-18T19:47:43.931Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-pxmc-2ffp-8j67"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "lemur",
          "vendor": "Netflix",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.9.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Lemur manages TLS certificate creation. Prior to 1.9.3, POST /api/1/certificates/upload allowed a non-read-only user to create a duplicate row using another certificate body, authority_id, serial, or external_id without requiring permission on the underlying authority. PUT /api/1/certificates//revoke authorized the caller against only the selected Lemur row, so the creator of the duplicate bypassed CertificatePermission. The duplicate had no cert.endpoints, which also bypassed the safeguard that prevents revocation of deployed certificates. Issuer plugins then revoked the real CA-side certificate using certificate.body or external_id under the stored authority credentials. An attacker could therefore revoke arbitrary managed certificates and cause fleet-wide TLS denial of service. The fix rejects duplicate authority_id and serial identities, requires authority access on upload, and checks every matching row during revocation. This issue is fixed in version 1.9.3."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-639",
              "description": "CWE-639: Authorization Bypass Through User-Controlled Key",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T19:12:16.427Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/Netflix/lemur/security/advisories/GHSA-pxmc-2ffp-8j67",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-pxmc-2ffp-8j67"
        },
        {
          "name": "https://github.com/Netflix/lemur/commit/851389ae737a6d6bf16c1f9ca64a2ce56c1cc5c6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Netflix/lemur/commit/851389ae737a6d6bf16c1f9ca64a2ce56c1cc5c6"
        },
        {
          "name": "https://github.com/Netflix/lemur/releases/tag/v1.9.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Netflix/lemur/releases/tag/v1.9.3"
        }
      ],
      "source": {
        "advisory": "GHSA-pxmc-2ffp-8j67",
        "discovery": "UNKNOWN"
      },
      "title": "Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-71417",
    "datePublished": "2026-08-18T19:12:16.427Z",
    "dateReserved": "2026-08-06T16:28:51.181Z",
    "dateUpdated": "2026-08-18T19:47:43.931Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

PYSEC-2026-3678

Vulnerability from pysec - Published: 2026-08-19 11:56 - Updated: 2026-08-19 12:16

Details

Summary

Repo under test: https://github.com/Netflix/lemur

Affected route

POST /api/1/certificates/upload → PUT /api/1/certificates/<dup_id>/revoke

Affected code

lemur/certificates/views.py:651 — only StrictRolePermission().can() gates upload; no AuthorityPermission check
lemur/certificates/schemas.py:391 — CertificateUploadInputSchema accepts caller-supplied authority and external_id
lemur/schemas.py:107 — AssociatedAuthoritySchema resolves any authority by id/name with no permission check
lemur/certificates/service.py:489 — upload() binds the caller-supplied authority onto the new row
lemur/certificates/models.py:119 — only name is unique; body/serial/external_id are not, and get_or_increase_name() auto-suffixes on collision
lemur/certificates/views.py:1677 — if g.current_user != cert.user: ... CertificatePermission ... — creator of the duplicate row bypasses the owner check
lemur/certificates/views.py:1687 — if cert.endpoints: ... — duplicate row has no endpoints, so the deployed-cert safeguard is bypassed
lemur/certificates/service.py:1120 — plugin = plugins.get(certificate.authority.plugin_name); plugin.revoke_certificate(certificate, reason)
lemur/plugins/lemur_acme/acme_handlers.py:268 — ACME revokes by certificate.body
lemur/plugins/lemur_digicert/plugin.py:477, lemur/plugins/lemur_entrust/plugin.py:321 — commercial CAs revoke by certificate.external_id
lemur/certificates/schemas.py:290 — CertificateOutputSchema exposes external_id, body, authority to any authenticated user

Impact

Root cause

Validated evidence

Static path trace, confirmed by code inspection (validation status: CONFIRMED):

Upload is gated only by StrictRolePermission (default-open to any non-read-only user) and accepts attacker-chosen authority + external_id + body without an AuthorityPermission check.
Certificate.body / external_id have no uniqueness constraint, so a duplicate row is created.
The revoke endpoint short-circuits the owner check when caller is the row creator, and the endpoint-attached guard inspects only the duplicate row.
Issuer plugins revoke at the CA using body / external_id taken from the duplicate row under the authority's stored CA credentials.

Proof of concept / reproducer

Status: reconstructed from source report (static control-flow trace; not executed against a live CA — revoking at a real CA is destructive).

Preconditions: attacker is an authenticated Lemur user holding any role other than read-only. <VICTIM_CERT_ID> is any certificate id readable via GET /api/1/certificates.

# 1. Read the victim's body / authority / external_id (exposed to any authenticated user)
curl -sS "<TARGET_BASE_URL>/api/1/certificates/<VICTIM_CERT_ID>" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  | jq '{body, external_id, authority: .authority.id}'

# 2. Upload a duplicate row aliasing the same CA-side certificate
curl -sS -X POST "<TARGET_BASE_URL>/api/1/certificates/upload" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{
        "name": "victim-dup",
        "owner": "attacker@example.com",
        "body": "<VICTIM_BODY_PEM>",
        "authority": {"id": <VICTIM_AUTHORITY_ID>},
        "externalId": "<VICTIM_EXTERNAL_ID>"
      }'
# → returns {"id": <DUP_ID>, ...}; attacker is now cert.user of <DUP_ID>

# 3. Revoke the duplicate — issuer plugin revokes at the CA by body/external_id
curl -sS -X PUT "<TARGET_BASE_URL>/api/1/certificates/<DUP_ID>/revoke" \
  -H "Authorization: Bearer <AUTH_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"crlReason": "unspecified"}'

Static-trace validation command from the source report:

grep -n 'StrictRolePermission' lemur/certificates/views.py | grep -v Authority
grep -n 'cert.authority = kwargs.get' lemur/certificates/service.py
grep -n 'g.current_user != cert.user' lemur/certificates/views.py
grep -n 'certificate.external_id\|certificate.body' \
  lemur/plugins/lemur_acme/acme_handlers.py \
  lemur/plugins/lemur_digicert/plugin.py \
  lemur/plugins/lemur_entrust/plugin.py

Suggested fix

Decouple CA-side revocation authority from Lemur row ownership:

On POST /certificates/upload, if authority is supplied enforce AuthorityPermission for that authority, and reject/ignore caller-supplied external_id.
Before calling plugin.revoke_certificate, look up all Certificate rows sharing the same (authority_id, serial) or body and require CertificatePermission on every match (and run the endpoint-attached check against all matches).
Consider a DB uniqueness constraint or dedup on (authority_id, serial) so a second row for the same CA-issued certificate cannot be created.
Stop exposing external_id in CertificateOutputSchema to non-owners.

Severity

7.3 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H

Impacted products

Name	purl
lemur	pkg:pypi/lemur

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lemur",
        "purl": "pkg:pypi/lemur"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.11.0",
        "0.2.1",
        "0.8.0",
        "0.8.1",
        "0.9.0",
        "1.0.0",
        "1.1.0",
        "1.2.0",
        "1.3.1",
        "1.3.2",
        "1.4.0",
        "1.5.0",
        "1.6.0",
        "1.7.0",
        "1.8.0",
        "1.8.1",
        "1.8.2",
        "1.9.0",
        "1.9.1",
        "1.9.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-71417",
    "GHSA-pxmc-2ffp-8j67"
  ],
  "details": "## Summary\n\nRepo under test: https://github.com/Netflix/lemur\n\n`PUT /api/1/certificates/\u003cid\u003e/revoke` authorizes the caller against the *Lemur database row* (creator == current user, or `CertificatePermission` over the row\u0027s roles) rather than the underlying CA-side certificate identity. Separately, `POST /api/1/certificates/upload` lets any user passing `StrictRolePermission` create a new `Certificate` row while freely supplying `body`, `authority` (resolved by id/name with no `AuthorityPermission` check) and `external_id`; there is no uniqueness constraint on `body`, `serial`, or `external_id`.\n\nAn attacker can therefore read a target certificate\u0027s public `body`, `authority.id`, and `external_id` via `GET /certificates/\u003cid\u003e`, upload a duplicate row, and revoke that duplicate. The creator-bypass skips `CertificatePermission`, the empty-endpoints check passes because the duplicate has none, and `service.revoke()` then revokes at the CA using the attacker-supplied `body` (ACME) or `external_id` (DigiCert/Entrust/Google CA/CFSSL) under the authority\u0027s stored CA credentials \u2014 revoking the real production certificate.\n\n## Affected route\n\n`POST /api/1/certificates/upload` \u2192 `PUT /api/1/certificates/\u003cdup_id\u003e/revoke`\n\n## Affected code\n\n- [`lemur/certificates/views.py:651`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L651) \u2014 only `StrictRolePermission().can()` gates upload; no `AuthorityPermission` check\n- [`lemur/certificates/schemas.py:391`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/schemas.py#L391) \u2014 `CertificateUploadInputSchema` accepts caller-supplied `authority` and `external_id`\n- [`lemur/schemas.py:107`](https://github.com/Netflix/lemur/blob/main/lemur/schemas.py#L107) \u2014 `AssociatedAuthoritySchema` resolves any authority by id/name with no permission check\n- [`lemur/certificates/service.py:489`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/service.py#L489) \u2014 `upload()` binds the caller-supplied authority onto the new row\n- [`lemur/certificates/models.py:119`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/models.py#L119) \u2014 only `name` is unique; `body`/`serial`/`external_id` are not, and `get_or_increase_name()` auto-suffixes on collision\n- [`lemur/certificates/views.py:1677`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L1677) \u2014 `if g.current_user != cert.user: ... CertificatePermission ...` \u2014 creator of the duplicate row bypasses the owner check\n- [`lemur/certificates/views.py:1687`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/views.py#L1687) \u2014 `if cert.endpoints: ...` \u2014 duplicate row has no endpoints, so the deployed-cert safeguard is bypassed\n- [`lemur/certificates/service.py:1120`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/service.py#L1120) \u2014 `plugin = plugins.get(certificate.authority.plugin_name); plugin.revoke_certificate(certificate, reason)`\n- [`lemur/plugins/lemur_acme/acme_handlers.py:268`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_acme/acme_handlers.py#L268) \u2014 ACME revokes by `certificate.body`\n- [`lemur/plugins/lemur_digicert/plugin.py:477`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_digicert/plugin.py#L477), [`lemur/plugins/lemur_entrust/plugin.py:321`](https://github.com/Netflix/lemur/blob/main/lemur/plugins/lemur_entrust/plugin.py#L321) \u2014 commercial CAs revoke by `certificate.external_id`\n- [`lemur/certificates/schemas.py:290`](https://github.com/Netflix/lemur/blob/main/lemur/certificates/schemas.py#L290) \u2014 `CertificateOutputSchema` exposes `external_id`, `body`, `authority` to any authenticated user\n\n## Impact\n\nA low-privileged authenticated insider (or holder of a stolen non-admin token/API key) can revoke any certificate managed by Lemur \u2014 including high-value certificates they do not own and certificates currently attached to live endpoints \u2014 directly at the issuing CA. Iterating over `GET /certificates` yields fleet-wide revocation (mass DoS of TLS endpoints) without ever passing an `AuthorityPermission` or `CertificatePermission` check on the victim certificate. This is exactly the \"Revocation as DoS vector\" scenario flagged in the threat model and additionally defeats the built-in \"cannot revoke while attached to endpoint\" safeguard.\n\n## Root cause\n\nRevocation authority is bound to ownership of the Lemur DB row, not to the CA-side certificate identity. Because upload allows creating a second row that aliases the same CA-side certificate (same `body` / `external_id` / `authority`) without any uniqueness constraint or `AuthorityPermission` check, the attacker can manufacture a row they own and then exercise the creator-bypass on revoke. The endpoint-attached guard inspects only the duplicate row\u0027s `cert.endpoints`, which is empty.\n\n## Validated evidence\n\nStatic path trace, confirmed by code inspection (validation status: `CONFIRMED`):\n\n- Upload is gated only by `StrictRolePermission` (default-open to any non-read-only user) and accepts attacker-chosen `authority` + `external_id` + `body` without an `AuthorityPermission` check.\n- `Certificate.body` / `external_id` have no uniqueness constraint, so a duplicate row is created.\n- The revoke endpoint short-circuits the owner check when caller is the row creator, and the endpoint-attached guard inspects only the duplicate row.\n- Issuer plugins revoke at the CA using `body` / `external_id` taken from the duplicate row under the authority\u0027s stored CA credentials.\n\n## Proof of concept / reproducer\n\nStatus: reconstructed from source report (static control-flow trace; not executed against a live CA \u2014 revoking at a real CA is destructive).\n\nPreconditions: attacker is an authenticated Lemur user holding any role other than `read-only`. `\u003cVICTIM_CERT_ID\u003e` is any certificate id readable via `GET /api/1/certificates`.\n\n```bash\n# 1. Read the victim\u0027s body / authority / external_id (exposed to any authenticated user)\ncurl -sS \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/\u003cVICTIM_CERT_ID\u003e\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  | jq \u0027{body, external_id, authority: .authority.id}\u0027\n\n# 2. Upload a duplicate row aliasing the same CA-side certificate\ncurl -sS -X POST \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/upload\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\n        \"name\": \"victim-dup\",\n        \"owner\": \"attacker@example.com\",\n        \"body\": \"\u003cVICTIM_BODY_PEM\u003e\",\n        \"authority\": {\"id\": \u003cVICTIM_AUTHORITY_ID\u003e},\n        \"externalId\": \"\u003cVICTIM_EXTERNAL_ID\u003e\"\n      }\u0027\n# \u2192 returns {\"id\": \u003cDUP_ID\u003e, ...}; attacker is now cert.user of \u003cDUP_ID\u003e\n\n# 3. Revoke the duplicate \u2014 issuer plugin revokes at the CA by body/external_id\ncurl -sS -X PUT \"\u003cTARGET_BASE_URL\u003e/api/1/certificates/\u003cDUP_ID\u003e/revoke\" \\\n  -H \"Authorization: Bearer \u003cAUTH_TOKEN\u003e\" \\\n  -H \"Content-Type: application/json\" \\\n  -d \u0027{\"crlReason\": \"unspecified\"}\u0027\n```\n\nStatic-trace validation command from the source report:\n\n```bash\ngrep -n \u0027StrictRolePermission\u0027 lemur/certificates/views.py | grep -v Authority\ngrep -n \u0027cert.authority = kwargs.get\u0027 lemur/certificates/service.py\ngrep -n \u0027g.current_user != cert.user\u0027 lemur/certificates/views.py\ngrep -n \u0027certificate.external_id\\|certificate.body\u0027 \\\n  lemur/plugins/lemur_acme/acme_handlers.py \\\n  lemur/plugins/lemur_digicert/plugin.py \\\n  lemur/plugins/lemur_entrust/plugin.py\n```\n\nSource artifact: `audit/harnesses/public-repo-threat-model-harness/results/netflix-lemur-100run-mythos-20260627T051129Z/findings.jsonl` (run_050, finding cluster `lemur-revoke-via-duplicate`, 2/100 runs).\n\n## Suggested fix\n\nDecouple CA-side revocation authority from Lemur row ownership:\n\n1. On `POST /certificates/upload`, if `authority` is supplied enforce `AuthorityPermission` for that authority, and reject/ignore caller-supplied `external_id`.\n2. Before calling `plugin.revoke_certificate`, look up all `Certificate` rows sharing the same `(authority_id, serial)` or `body` and require `CertificatePermission` on every match (and run the endpoint-attached check against all matches).\n3. Consider a DB uniqueness constraint or dedup on `(authority_id, serial)` so a second row for the same CA-issued certificate cannot be created.\n4. Stop exposing `external_id` in `CertificateOutputSchema` to non-owners.",
  "id": "PYSEC-2026-3678",
  "modified": "2026-08-19T12:16:27.578924Z",
  "published": "2026-08-19T11:56:28.618014Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-pxmc-2ffp-8j67"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/commit/851389ae737a6d6bf16c1f9ca64a2ce56c1cc5c6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Netflix/lemur"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Netflix/lemur/releases/tag/v1.9.3"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/lemur"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-pxmc-2ffp-8j67"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71417"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-PXMC-2FFP-8J67

Summary

Affected route

Affected code

Impact

Root cause

Validated evidence

Proof of concept / reproducer

Suggested fix

CVE-2026-71417 (GCVE-0-2026-71417)

PYSEC-2026-3678

Summary

Affected route

Affected code

Impact

Root cause

Validated evidence

Proof of concept / reproducer

Suggested fix

Tags

Sightings

Nomenclature