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.
References
Configurations
Configuration 1 (hide)
|
History
08 Oct 2026, 01:20
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* | |
| First Time |
Openssl openssl
Openssl |
|
| References | () https://github.com/openssl/openssl/commit/1c4aed808a7aea32d2d013049c2e0d9fef164fc9 - Patch | |
| References | () https://github.com/openssl/openssl/commit/20b20628d39b2dcc4677194bd68c7c060fa598cb - Patch | |
| References | () https://github.com/openssl/openssl/commit/419f5cb519721dceed393dbc524d79e487c72e64 - Patch | |
| References | () https://github.com/openssl/openssl/commit/6b90445a56b99a328ac1feba058abf976504f440 - Patch | |
| References | () https://openssl-library.org/news/secadv/20260929.txt - Vendor Advisory |
29 Sep 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 3.7 |
29 Sep 2026, 16:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-29 16:17
Updated : 2026-10-08 01:20
NVD link : CVE-2026-77696
Mitre link : CVE-2026-77696
CVE.ORG link : CVE-2026-77696
JSON object : View
Products Affected
openssl
- openssl
CWE
CWE-208
Observable Timing Discrepancy