CVE-2026-76957

MEDIUMPre-NVD 4.94.9—
EchelonGraph scoreHIGH confidence

Score 4.9 from GitHub Security Advisory published 2026-08-20. a secondary CVSS source baseline 4.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
Trending — 4 sources updated this week
4.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.

CVSS v3
4.9
EG Score
4.9(high)
EG Risk
22(Track)
EG Risk 22/100SSVC: Track

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
Severity49% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 20, 2026

Advisory Details (2)

Auto-updated Aug 20, 2026
No patch confirmed yet. Sources: github_pr.
github_pr

Prepare release 2.8.4 (part of #1328, ETA 2026-08-31)

Upstream fix in progress (PR #1329 · libexpat/libexpat, state=open)

https://github.com/libexpat/libexpat/pull/1329
github_pr

[CVE-REQUESTED] Protect custom encoding callbacks from parser re-entry

Upstream fix in progress (PR #1322 · libexpat/libexpat, state=open)

https://github.com/libexpat/libexpat/pull/1322

Vendor Advisories for CVE-2026-76957(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 8× 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. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 16:34 UTCEG score recompute
  3. 2026-08-20 16:34 UTCGHSA enrichment
  4. 2026-08-20 15:45 UTCEG score recompute
  5. 2026-08-20 15:45 UTCGHSA enrichment
  6. 2026-08-20 05:20 UTCEG score recompute
  7. 2026-08-20 04:38 UTCEG score recompute
  8. 2026-08-20 04:37 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-76957?
CVE-2026-76957 is a medium vulnerability published on August 20, 2026. libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
When was CVE-2026-76957 disclosed?
CVE-2026-76957 was first published in the National Vulnerability Database on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76957 actively exploited?
CVE-2026-76957 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.9% of all scored CVEs.
What is the CVSS score of CVE-2026-76957?
CVE-2026-76957 has a CVSS v3 base score of 4.9 (NVD).
How do I remediate CVE-2026-76957?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76957, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-76957

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