CVE-2026-77696

NameCVE-2026-77696
DescriptionIssue summary: SM2 signature generation uses non-constant-time arithmetic on secret values, forming a timing side-channel. Impact summary: An attacker able to measure SM2 signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: SM2 signature generation computes the signature value using variable-time BIGNUM operations on the secret nonce and the private key, so the time taken to produce an SM2 signature depends on these secret values, forming a timing side-channel. Applications performing SM2 signature generation are affected on all platforms. FIPS Impact: no SM2 is not a FIPS algorithm.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6531-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)bookworm3.0.20-1~deb12u2vulnerable
bookworm (security)3.0.22-1~deb12u1vulnerable
trixie3.5.7-1~deb13u2vulnerable
trixie (security)3.5.7-1~deb13u3fixed
forky3.6.4-1vulnerable
sid3.6.5-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcetrixie3.5.7-1~deb13u3DSA-6531-1
opensslsource(unstable)3.6.5-1

Notes

https://openssl-library.org/news/secadv/20260929.txt

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