{"api_version":"1","generated_at":"2026-10-09T11:08:56+00:00","cve":"CVE-2026-77696","urls":{"html":"https://cve.report/CVE-2026-77696","api":"https://cve.report/api/cve/CVE-2026-77696.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-77696","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-77696"},"summary":{"title":"Timing Side-Channel in SM2 Signature Generation","description":"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.","state":"PUBLISHED","assigner":"openssl","published_at":"2026-09-29 16:17:11","updated_at":"2026-09-29 21:27:41"},"problem_types":["CWE-208","CWE-208 CWE-208 Observable Timing 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Generation","CVE":"CVE-2026-77696","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"77696","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Timing Side-Channel in SM2 Signature Generation"}]}}}