CVE-2026-77696
Description
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.
How to fix
- openssl openssl1.1.1zj, 3.0.23, 3.4.8, 3.5.9, 3.6.5, 4.0.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| openssl openssl | 1.1.1 ≤ v < 1.1.1zj, 3.0.0 ≤ v < 3.0.23, 3.4.0 ≤ v < 3.4.8, 3.5.0 ≤ v < 3.5.9, 3.6.0 ≤ v < 3.6.5, 4.0.0 ≤ v < 4.0.3 | 1.1.1zj, 3.0.23, 3.4.8, 3.5.9, 3.6.5, 4.0.3 |
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