{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "OpenSSL",
          "vendor": "OpenSSL",
          "versions": [
            {
              "lessThan": "4.0.3",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.6.5",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.5.9",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.4.8",
              "status": "affected",
              "version": "3.4.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.0.23",
              "status": "affected",
              "version": "3.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.1.1zj",
              "status": "affected",
              "version": "1.1.1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Vladimir Tokarev"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Igor Ustinov"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Viktor Dukhovni"
        }
      ],
      "datePublic": "2026-09-29T16:21:57+02:00",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Issue summary: SM2 signature generation uses non-constant-time arithmetic<br>on secret values, forming a timing side-channel.<br><br>Impact summary: An attacker able to measure SM2 signing times may learn<br>information about the per-signature secret nonce, which over many signatures<br>can, via a lattice / Hidden Number Problem attack, lead to recovery of the<br>private key.<br><br>CWE: CWE-208: Observable Timing Discrepancy<br><br>Description: SM2 signature generation computes the signature value using<br>variable-time BIGNUM operations on the secret nonce and the private key, so<br>the time taken to produce an SM2 signature depends on these secret values,<br>forming a timing side-channel.<br><br>Applications performing SM2 signature generation are affected on all<br>platforms.<br><br>FIPS Impact: no<br>SM2 is not a FIPS algorithm."
            }
          ],
          "value": "Issue summary: SM2 signature generation uses non-constant-time arithmetic\non secret values, forming a timing side-channel.\n\nImpact summary: An attacker able to measure SM2 signing times may learn\ninformation about the per-signature secret nonce, which over many signatures\ncan, via a lattice / Hidden Number Problem attack, lead to recovery of the\nprivate key.\n\nCWE: CWE-208: Observable Timing Discrepancy\n\nDescription: SM2 signature generation computes the signature value using\nvariable-time BIGNUM operations on the secret nonce and the private key, so\nthe time taken to produce an SM2 signature depends on these secret values,\nforming a timing side-channel.\n\nApplications performing SM2 signature generation are affected on all\nplatforms.\n\nFIPS Impact: no\nSM2 is not a FIPS algorithm."
        }
      ],
      "metrics": [
        {
          "format": "other",
          "other": {
            "content": {
              "text": "Low"
            },
            "type": "https://openssl-library.org/policies/general/security-policy/"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-208",
              "description": "CWE-208 Observable Timing Discrepancy",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "orgId": "00000000-0000-4000-9000-000000000000",
        "shortName": "openssl"
      },
      "references": [
        {
          "name": "OpenSSL Advisory",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://openssl-library.org/news/secadv/20260929.txt"
        },
        {
          "name": "4.0.3 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/20b20628d39b2dcc4677194bd68c7c060fa598cb"
        },
        {
          "name": "3.6.5 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/1c4aed808a7aea32d2d013049c2e0d9fef164fc9"
        },
        {
          "name": "3.5.9 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/6b90445a56b99a328ac1feba058abf976504f440"
        },
        {
          "name": "3.4.8 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/419f5cb519721dceed393dbc524d79e487c72e64"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Timing Side-Channel in SM2 Signature Generation",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "00000000-0000-4000-9000-000000000000",
    "cveId": "CVE-2026-77696",
    "requesterUserId": "00000000-0000-4000-9000-000000000000",
    "serial": 1,
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}