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.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
libexpat project libexpat unaffected
Version Status Constraints
0 affected < 2.8.4

No data.

No data.

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Vendors Products
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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/libexpat/libexpat/pull/1322 cve-icon cve-icon
https://github.com/libexpat/libexpat/pull/1329 cve-icon cve-icon
History

Thu, 20 Aug 2026 07:45:00 +0000

Type Values Removed Values Added
Title Use-After-Free in libexpat Due to Missing Handler Depth Tracking for Custom Encoding Callbacks

Thu, 20 Aug 2026 04:45:00 +0000

Type Values Removed Values Added
Description 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.
First Time appeared Libexpat Project
Libexpat Project libexpat
Weaknesses CWE-416
CPEs cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
Vendors & Products Libexpat Project
Libexpat Project libexpat
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-08-20T04:28:04.788Z

Reserved: 2026-08-20T04:28:04.012Z

Link: CVE-2026-76957

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-20T05:16:29.747

Modified: 2026-08-20T05:16:29.747

Link: CVE-2026-76957

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-20T07:30:03Z

Weaknesses