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.
CVSS Details
- CVSS 3.1 Base Score: 3.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade openssl | Oct 1, 2026 | Sep 29, 2026 |
| Debian | — | Upgrade openssl | Oct 1, 2026 | Sep 29, 2026 |
| Http Openssl | — | Upgrade to the latest version of OpenSSL | Sep 30, 2026 | Sep 29, 2026 |
| Redhat_linux | — | No solution exists | Oct 1, 2026 | Sep 29, 2026 |
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