CVE-2026-77696 Affecting openssl package, versions <3.6.5-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-OPENSSL-20267536
  • published30 Sept 2026
  • disclosed29 Sept 2026

Introduced: 29 Sep 2026

NewCVE-2026-77696  (opens in a new tab)

How to fix?

Upgrade Debian:unstable openssl to version 3.6.5-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 Base Scores

version 3.1