CVE-2026-77696

LOWPre-NVD 3.73.7—
EchelonGraph scoreHIGH confidence

Score 3.7 from GitHub Security Advisory (severity: LOW) published 2026-09-29. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 3.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — Patch released this week
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 3.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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 v3
3.7
EG Score
3.7LOWhigh confidence
EG Risk
17
EG Risk 17/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity37% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
14th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2026

Last Modified

September 29, 2026

References (5)

Vendor Advisories for CVE-2026-77696(4)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuopenssl1.0 (1.0.2n-1ubuntu5.13+esm7) @ bionic2026-10-03ubuntu
ubuntuopenssl (3.0.2-0ubuntu1.30) @ jammy2026-10-03ubuntu
redhatopenssl-main-3.5.9-0.1.hum12026-09-30redhat
redhatopenssl3-main-3.5.9-0.1.hum12026-09-30redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 13× in last 7d / 13× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-03 14:26 UTCEPSS rescore
  2. 2026-10-03 01:34 UTCEG score recompute
  3. 2026-10-03 01:34 UTCVendor advisory
  4. 2026-10-03 01:34 UTCGHSA enrichment
  5. 2026-10-01 19:50 UTCEPSS rescore
  6. 2026-09-29 22:00 UTCEG score recompute
  7. 2026-09-29 22:00 UTCVendor advisory
  8. 2026-09-29 22:00 UTCGHSA enrichment
  9. 2026-09-29 16:54 UTCEG score recompute▲ 3.70
  10. 2026-09-29 16:53 UTCMITRE cvelistV5CVSS v3 → 3.7 · severity → LOW
  11. 2026-09-29 16:24 UTCNVD update
  12. 2026-09-29 15:38 UTCEG score recompute
  13. 2026-09-29 15:38 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-77696?
CVE-2026-77696 is a low vulnerability published on September 29, 2026. 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…
When was CVE-2026-77696 disclosed?
CVE-2026-77696 was first published on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77696 actively exploited?
CVE-2026-77696 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77696?
CVE-2026-77696 has a CVSS v3.1 base score of 3.7 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-77696?
A fix for CVE-2026-77696 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77696 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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