CVE-2026-76641

HIGHPre-NVD 7.57.5
EchelonGraph scoreLOW confidence

This high-severity CVE scores 7.5 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:vulncheck
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 7.5Exploit: None knownExposed: 0

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

Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.

CVSS v3
7.5
EG Score
7.5(low)
EG Risk
38(Track)
EG Risk 38/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

Published

August 20, 2026

Last Modified

August 20, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr, github_commit.
generic

Expat Out-of-Bounds Read via dtdCopy | Advisories | VulnCheck

https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy
github_commit

commit 98599f6dcc2b (libexpat/libexpat)

Fix landed in libexpat/libexpat commit 98599f6dcc2b — awaiting tagged release

https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf
github_pr

[CVE-2026-76641] lib: Fix out-of-bounds read from hash table entries created by dtdCopy

Fix merged in libexpat/libexpat PR #1331 on 2026-08-20 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1331

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 2× in last 7d / 2× 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 17:46 UTCEG score recompute
  2. 2026-08-20 17:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(4)

What is CVE-2026-76641?
CVE-2026-76641 is a high vulnerability published on August 20, 2026. Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XMLExternalEntityParserCreate. A struct size mismatch between ELEMENTTYPE members causes storeAtts to read the attIndex…
When was CVE-2026-76641 disclosed?
CVE-2026-76641 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.
What is the CVSS score of CVE-2026-76641?
CVE-2026-76641 has a CVSS v4.0 base score of 7.5 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-76641?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76641, 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

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