CVE intelligence

CVE-2026-77696

Vulnerability intelligence

Published Sep 29, 2026Sources checked Nov 14, 2026

3.7LOWCVSS out of 10

What this means

Review the available evidence

CVE-2026-77696 and is rated Low severity with a CVSS score of 3.7. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 16, 2026

Release Notes

Vendor-listed releases

20240524git3e722403cd16-21
3.3.7-7

Ubuntu Security Notices guidance

Vendor revision: Sep 29, 2026

USN-8847-1 fixed vulnerabilities in OpenSSL.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-77696?

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.

Source: NVD