Vulnerability-Lookup

OSEC-2026-17

Vulnerability from osv_ocaml

Published

2026-08-17 09:45

Modified

2026-09-10 09:45

Summary

Timing leak in NIST elliptic curves scalar multiplication

Details

The scalar multiplication includes pre-computed tables for speedup (introduced in mirage-crypto-ec 0.11.3). The lookup algorithm for these tables performs secret-dependent reads instead of scanning the entire table.

Solution

Instead of using the index n - 1, where n is secret-dependent, use i - 1, as done in the Go reference implementation. If n is 0, there is a out-of-bounds read before the patch.

Timeline

2026-08-12: report by Eric Ebinger to security@ocaml.org
2026-08-17: release of mirage-crypto-ec 2.4.0 and this advisory

Severity

5.9 (Medium)


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

Credits

Eric Ebinger

Hannes Mehnert

Virgile Robles

Eric Ebinger

JSON

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{
  "affected": [
    {
      "ecosystem_specific": {
        "affected_bindings": [
          "Mirage_crypto_ec.P256.Dh.share",
          "Mirage_crypto_ec.P256.Dsa.generate",
          "Mirage_crypto_ec.P256.Dsa.sign",
          "Mirage_crypto_ec.P256.Dsa.pub_of_priv",
          "Mirage_crypto_ec.P384.Dh.share",
          "Mirage_crypto_ec.P384.Dsa.generate",
          "Mirage_crypto_ec.P384.Dsa.sign",
          "Mirage_crypto_ec.P384.Dsa.pub_of_priv",
          "Mirage_crypto_ec.P521.Dh.share",
          "Mirage_crypto_ec.P521.Dsa.generate",
          "Mirage_crypto_ec.P521.Dsa.sign",
          "Mirage_crypto_ec.P521.Dsa.pub_of_priv"
        ],
        "opam_constraint": "mirage-crypto-ec {\u003e= \"0.11.3\" \u0026 \u003c \"2.4.0\"}"
      },
      "package": {
        "ecosystem": "opam",
        "name": "mirage-crypto-ec",
        "purl": "pkg:opam/mirage-crypto-ec"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.11.3"
            },
            {
              "fixed": "2.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1a61aeee7f593ec067612df1739ec905eab0450f"
            }
          ],
          "repo": "https://github.com/mirage/mirage-crypto",
          "type": "GIT"
        }
      ],
      "versions": [
        "0.11.3",
        "1.0.0",
        "1.1.0",
        "1.2.0",
        "2.0.0",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.1.0",
        "2.2.0",
        "2.3.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-87737"
  ],
  "credits": [
    {
      "name": "Eric Ebinger",
      "type": "REPORTER"
    },
    {
      "name": "Hannes Mehnert",
      "type": "COORDINATOR"
    },
    {
      "name": "Virgile Robles",
      "type": "REMEDIATION_REVIEWER"
    },
    {
      "name": "Eric Ebinger",
      "type": "REMEDIATION_DEVELOPER"
    }
  ],
  "database_specific": {
    "cwe": [
      "CWE-208"
    ],
    "human_link": "https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-17.md",
    "osv": "https://github.com/ocaml/security-advisories/tree/generated-osv/2026/OSEC-2026-17.json"
  },
  "details": "The scalar multiplication includes pre-computed tables for speedup (introduced in mirage-crypto-ec 0.11.3). The lookup algorithm for these tables performs secret-dependent reads instead of scanning the entire table.\n\n## Solution\n\nInstead of using the index `n - 1`, where `n` is secret-dependent, use `i - 1`, as done in the Go reference implementation. If `n` is 0, there is a out-of-bounds read before the patch.\n\n## Timeline\n- 2026-08-12: report by Eric Ebinger to security@ocaml.org\n- 2026-08-17: release of mirage-crypto-ec 2.4.0 and this advisory",
  "id": "OSEC-2026-17",
  "modified": "2026-09-10T09:45:00Z",
  "published": "2026-08-17T09:45:00Z",
  "references": [],
  "schema_version": "1.7.4",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Timing leak in NIST elliptic curves scalar multiplication"
}

CVE-2026-87737 (GCVE-0-2026-87737)

Vulnerability from cvelistv5 – Published: 2026-09-09 04:21 – Updated: 2026-09-09 13:10

Summary

An issue was discovered in the mirage-crypto-ec package before 2.4.0 for OCaml. There is a timing side channel for NIST elliptic-curve scalar multiplication: the time required for a lookup can depend on a secret.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-09 13:09 UTC

CWE

CWE-208 - Observable Timing Discrepancy

Assigner

mitre mitre root

References

1 reference

URL	Tags
https://osv.dev/vulnerability/OSEC-2026-17

Impacted products

1 product

Vendor	Product	Version
OCaml	mirage-crypto-ec	Affected: 0 , < 2.4.0 (semver)

Show details on NVD website

JSON

To clipboard

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                "timestamp": "2026-09-09T13:09:56.811729Z",
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        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
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      "references": [
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          "url": "https://osv.dev/vulnerability/OSEC-2026-17"
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  "cveMetadata": {
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    "cveId": "CVE-2026-87737",
    "datePublished": "2026-09-09T04:21:37.602Z",
    "dateReserved": "2026-09-09T04:21:37.242Z",
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.