osec-2026-14
Vulnerability from osv_ocaml
Published
2026-08-07 13:00
Modified
2026-08-07 13:00
Summary
RSA signature verification raises undocumented exception
Details

The RSA decrypt and encrypt functions raise an Invalid_argument exception if the message is smaller than 2. This leads to X509 certificates with a signature value of 0 or 1 to throw this Invalid_argument exception instead of a proper error.

Fix

The fix is to reuse the Insufficient_key exception, which is documented and caught further up in the stack.

Timeline

  • July 28th 2026: report to security@ocaml.org
  • August 7th: release of mirage-crypto-pk 2.3.0 and security advisory
Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Credits
Thomas Gazagnaire
Hannes Mehnert
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "affected_bindings": [
          "Mirage_crypto_pk.Rsa.encrypt",
          "Mirage_crypto_pk.Rsa.decrypt",
          "Mirage_crypto_pk.Rsa.PKCS1.encrypt",
          "Mirage_crypto_pk.Rsa.PKCS1.decrypt",
          "Mirage_crypto_pk.Rsa.PKCS1.sig_encode",
          "Mirage_crypto_pk.Rsa.PKCS1.sig_decode",
          "Mirage_crypto_pk.Rsa.PKCS1.sign",
          "Mirage_crypto_pk.Rsa.PKCS1.verify",
          "Mirage_crypto_pk.Rsa.OAEP.encrypt",
          "Mirage_crypto_pk.Rsa.OAEP.decrypt",
          "Mirage_crypto_pk.Rsa.PSS.sign",
          "Mirage_crypto_pk.Rsa.PSS.verify"
        ],
        "opam_constraint": "mirage-crypto-pk {\u003c \"2.3.0\"}"
      },
      "package": {
        "ecosystem": "opam",
        "name": "mirage-crypto-pk",
        "purl": "pkg:opam/mirage-crypto-pk"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a0f59a0c90eb067505b55a03d3bb104eacd6dd33"
            }
          ],
          "repo": "https://github.com/mirage/mirage-crypto.git",
          "type": "GIT"
        }
      ],
      "versions": [
        "0.6.0",
        "0.6.1",
        "0.6.2",
        "0.7.0",
        "0.8.0",
        "0.8.1",
        "0.8.2",
        "0.8.3",
        "0.8.4",
        "0.8.5",
        "0.8.6",
        "0.8.7",
        "0.8.8",
        "0.8.9",
        "0.8.10",
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "0.10.0",
        "0.10.1",
        "0.10.2",
        "0.10.3",
        "0.10.4",
        "0.10.5",
        "0.10.6",
        "0.10.7",
        "0.11.0",
        "0.11.1",
        "0.11.2",
        "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"
      ]
    }
  ],
  "credits": [
    {
      "name": "Thomas Gazagnaire",
      "type": "REPORTER"
    },
    {
      "name": "Hannes Mehnert",
      "type": "REMEDIATION_DEVELOPER"
    }
  ],
  "database_specific": {
    "cwe": [
      "CWE-248"
    ],
    "human_link": "https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-14.md",
    "osv": "https://github.com/ocaml/security-advisories/tree/generated-osv/2026/OSEC-2026-14.json"
  },
  "details": "The RSA decrypt and encrypt functions raise an Invalid_argument exception if the\nmessage is smaller than 2. This leads to X509 certificates with a signature\nvalue of 0 or 1 to throw this Invalid_argument exception instead of a proper\nerror.\n\n## Fix\n\nThe fix is to reuse the Insufficient_key exception, which is documented and\ncaught further up in the stack.\n\n## Timeline\n\n- July 28th 2026: report to security@ocaml.org\n- August 7th: release of mirage-crypto-pk 2.3.0 and security advisory",
  "id": "OSEC-2026-14",
  "modified": "2026-08-07T13:00:00Z",
  "published": "2026-08-07T13:00:00Z",
  "references": [],
  "schema_version": "1.7.4",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "RSA signature verification raises undocumented exception"
}



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