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CVE-2026-77696

Timing Side-Channel in SM2 Signature Generation PUBLISHED

Description (CNA)

Issue 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.

Affected (CNA)

Vendor / productVersions
OpenSSL / OpenSSLaffected 4.0.0 before 4.0.3; affected 3.6.0 before 3.6.5; affected 3.5.0 before 3.5.9; affected 3.4.0 before 3.4.8; affected 3.0.0 before 3.0.23; affected 1.1.1 before 1.1.1zj

CWE

CWE-208

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.