CVE-2026-77696 Affecting openssl1.0 package, versions <1.0.2n-1ubuntu5.13+esm7


Severity

Recommended
low

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-UBUNTU1804-OPENSSL10-20267084
  • published30 Sept 2026
  • disclosed29 Sept 2026

Introduced: 29 Sep 2026

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

How to fix?

Upgrade Ubuntu:18.04 openssl1.0 to version 1.0.2n-1ubuntu5.13+esm7 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl1.0 package and not the openssl1.0 package as distributed by Ubuntu. See How to fix? for Ubuntu:18.04 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