Vulnerability-Lookup

CVE-2026-85221 (GCVE-0-2026-85221)

Vulnerability from cvelistv5 – Published: 2026-09-03 14:16 – Updated: 2026-09-03 14:22

Title

MISP CurlClient TLS Peer Verification Disabled by Default Enables Man-in-the-Middle Attacks

Summary

MISP contains an improper TLS certificate validation vulnerability in CurlClient. The CurlClient::$verifyPeer property was not explicitly initialized and therefore defaulted to null. When passed to cURL, this value effectively disabled TLS peer verification unless the calling code explicitly enabled it. As a result, HTTPS connections made through affected CurlClient instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack. Successful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using CurlClient and the data exchanged with the remote service. The patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in SyncTool so that peer verification is disabled only when no pinned CA certificate is configured.

Severity

7.6 (High)


                        
                          CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-03 14:22 UTC

CWE

CWE-295 - Improper Certificate Validation

Assigner

CIRCL ENISA root

References

1 reference

URL	Tags
https://github.com/MISP/MISP/commit/e06f69858	patch

Impacted products

1 product

Vendor	Product	Version	CPE status
misp	misp	Affected: 0 , ≤ 2.5.45 (semver)	guessed

Credits

Andras Iklody (the Insomniac MISP lead dev) Claude Opus 5 (1M context) elhoim (David André)

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-85221

Vulnerability from fkie_nvd - Published: 2026-09-03 15:17 - Updated: 2026-09-03 16:45

Severity

7.6 (High) - CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	5a6e4751-2f3f-4070-9419-94fb35b644e8	https://github.com/MISP/MISP/commit/e06f69858

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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}

GCVE-1-2026-20085 (CVE-2026-85221)

Vulnerability from gna-1 – Published: 2026-09-03 14:16 – Updated: 2026-09-03 14:16

Title

MISP CurlClient TLS Peer Verification Disabled by Default Enables Man-in-the-Middle Attacks

Summary

Severity

7.6 (High)


                        
                          CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CWE

CWE-295 - Improper Certificate Validation

Assigner

GNA-1

References

1 reference

URL	Tags
https://github.com/MISP/MISP/commit/e06f69858	patch

Impacted products

1 product

Vendor	Product	Version
misp	misp	Affected: 0 , ≤ 2.5.45 (semver)

Credits

Andras Iklody (the Insomniac MISP lead dev) Claude Opus 5 (1M context) elhoim (David André)

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "misp",
          "repo": "https://github.com/MISP/MISP",
          "vendor": "misp",
          "versions": [
            {
              "lessThanOrEqual": "2.5.45",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Andras Iklody"
        },
        {
          "lang": "en",
          "type": "tool",
          "value": "Claude Opus 5 (1M context)"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "elhoim (David Andr\u00e9)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eMISP contains an improper TLS certificate validation vulnerability in \u003ccode\u003eCurlClient\u003c/code\u003e. The \u003ccode\u003eCurlClient::$verifyPeer\u003c/code\u003e property was not explicitly initialized and therefore defaulted to \u003ccode\u003enull\u003c/code\u003e. When passed to cURL, this value effectively disabled TLS peer verification unless the calling code explicitly enabled it.\u003c/p\u003e\n\u003cp\u003eAs a result, HTTPS connections made through affected \u003ccode\u003eCurlClient\u003c/code\u003e instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack.\u003c/p\u003e\n\u003cp\u003eSuccessful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using \u003ccode\u003eCurlClient\u003c/code\u003e and the data exchanged with the remote service.\u003c/p\u003e\n\u003cp\u003eThe patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in \u003ccode\u003eSyncTool\u003c/code\u003e so that peer verification is disabled only when no pinned CA certificate is configured.\u003c/p\u003e\u003cbr\u003e"
            }
          ],
          "value": "MISP contains an improper TLS certificate validation vulnerability in CurlClient. The CurlClient::$verifyPeer property was not explicitly initialized and therefore defaulted to null. When passed to cURL, this value effectively disabled TLS peer verification unless the calling code explicitly enabled it.\n\n\nAs a result, HTTPS connections made through affected CurlClient instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack.\n\n\nSuccessful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using CurlClient and the data exchanged with the remote service.\n\n\nThe patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in SyncTool so that peer verification is disabled only when no pinned CA certificate is configured."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-94",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-94 Adversary in the Middle (AiTM)"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "attackVector": "ADJACENT",
            "baseScore": 7.6,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295 Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "orgId": "00000000-0000-4000-9000-000000000000"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/MISP/MISP/commit/e06f69858"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "MISP CurlClient TLS Peer Verification Disabled by Default Enables Man-in-the-Middle Attacks",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "00000000-0000-4000-9000-000000000000",
    "cveId": "CVE-2026-85221",
    "datePublished": "2026-09-03T14:16:48.294316Z",
    "dateReserved": "2026-09-03T14:16:56.730Z",
    "dateUpdated": "2026-09-03T14:16:56.806725Z",
    "requesterUserId": "00000000-0000-4000-9000-000000000000",
    "serial": 1,
    "state": "PUBLISHED",
    "vulnId": "gcve-1-2026-20085"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

GHSA-37PQ-FMVF-2FWX

Vulnerability from github – Published: 2026-09-03 15:32 – Updated: 2026-09-03 15:32

Details

As a result, HTTPS connections made through affected CurlClient instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack.

Successful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using CurlClient and the data exchanged with the remote service.

The patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in SyncTool so that peer verification is disabled only when no pinned CA certificate is configured.

Severity

7.6 (High)


                  
                    CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-85221"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-03T15:17:41Z",
    "severity": "HIGH"
  },
  "details": "MISP contains an improper TLS certificate validation vulnerability in CurlClient. The CurlClient::$verifyPeer property was not explicitly initialized and therefore defaulted to null. When passed to cURL, this value effectively disabled TLS peer verification unless the calling code explicitly enabled it.\n\n\nAs a result, HTTPS connections made through affected CurlClient instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack.\n\n\nSuccessful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using CurlClient and the data exchanged with the remote service.\n\n\nThe patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in SyncTool so that peer verification is disabled only when no pinned CA certificate is configured.",
  "id": "GHSA-37pq-fmvf-2fwx",
  "modified": "2026-09-03T15:32:26Z",
  "published": "2026-09-03T15:32:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85221"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MISP/MISP/commit/e06f69858"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

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

CVE-2026-85221 (GCVE-0-2026-85221)

FKIE_CVE-2026-85221

GCVE-1-2026-20085 (CVE-2026-85221)

GHSA-37PQ-FMVF-2FWX

Tags

Sightings

Nomenclature