{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-77696","assignerOrgId":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","state":"PUBLISHED","assignerShortName":"openssl","dateReserved":"2026-08-21T07:47:36.032Z","datePublished":"2026-09-29T15:32:22.520Z","dateUpdated":"2026-09-29T16:51:33.618Z"},"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":"2026-09-29T14:21:57.000Z","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":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","shortName":"openssl","dateUpdated":"2026-09-29T15:32:22.520Z"},"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"}},"adp":[{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":3.7,"attackVector":"NETWORK","baseSeverity":"LOW","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"HIGH","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"LOW"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-29T16:51:30.070097Z","id":"CVE-2026-77696","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-29T16:51:33.618Z"}}]}}