osec-2026-17
Vulnerability from osv_ocaml
Published
2026-08-17 09:45
Modified
2026-08-17 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
To clipboard 

{
  "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"
      ]
    }
  ],
  "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": "2026-08-17T09:45:00Z",
  "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"
}



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