{"schema":"threatline.record/2","record":{"id":"CVE-2026-77696","aliases":[],"summary":"Timing Side-Channel in SM2 Signature Generation","details":"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.","categories":["Libraries & packages"],"product":"OpenSSL","vendor":"OpenSSL","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","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"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"4.0.3","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"3.6.5","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"3.5.9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"3.4.8","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"3.0.23","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","source_modified_at":"2026-09-29T16:51:33.618Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"OpenSSL","ecosystem":null},"version":"1.1.1zj","basis":"first unaffected version stated in the CVE record"}],"cvss":3.7,"severity":"Low","kev":{"listed":false},"epss":{"probability":0.00243,"percentile":0.14668,"score_date":"2026-10-23"},"published_at":"2026-09-29T15:32:22.520Z","modified_at":"2026-09-29T16:51:33.618Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-77696","fetched_at":"2026-10-23T18:52:38.922436Z","source_modified_at":"2026-09-29T16:51:33.618Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-77696","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://openssl-library.org/news/secadv/20260929.txt","tags":["vendor-advisory"]},{"source":"CVE List","url":"https://github.com/openssl/openssl/commit/20b20628d39b2dcc4677194bd68c7c060fa598cb","tags":["patch"]},{"source":"CVE List","url":"https://github.com/openssl/openssl/commit/1c4aed808a7aea32d2d013049c2e0d9fef164fc9","tags":["patch"]},{"source":"CVE List","url":"https://github.com/openssl/openssl/commit/6b90445a56b99a328ac1feba058abf976504f440","tags":["patch"]},{"source":"CVE List","url":"https://github.com/openssl/openssl/commit/419f5cb519721dceed393dbc524d79e487c72e64","tags":["patch"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-09-29T16:51:30.070097Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-09-29T16:51:33.618Z","content_hash":"538a8107f0e314253109bb2e73c6c0b7b281f28da6eeee55a6948a121416aeeb"}}