CVE-2026-56412
Expat Use-After-Free Vulnerability
Description
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
INFO
Published Date :
June 21, 2026, 5:16 p.m.
Last Modified :
Oct. 25, 2026, 11:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update libexpat to version 2.8.2 or later.
- Apply relevant security patches for libexpat.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56412.
| URL | Resource |
|---|---|
| https://github.com/libexpat/libexpat/pull/1278 | Patch Issue Tracking |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56412 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56412
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56412 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56412 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: libexpat project, Description: libexpat antes de la versión 2.8.2 no considera XML_TOK_DATA_CHARS en doCdataSection y, por lo tanto, carece de seguimiento de la profundidad de las llamadas a los gestores para varias llamadas desde dentro de los gestores en casos de una violación de política. Así, un uso después de liberación puede ocurrir. NOTA: este problema existe debido a una corrección incompleta para CVE-2026-50219. -
Initial Analysis by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L Added CPE Configuration OR *cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:* versions up to (excluding) 2.8.2 Added Reference Type MITRE: https://github.com/libexpat/libexpat/pull/1278 Types: Issue Tracking, Patch -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 22, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-56412', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-22T16:30:58.502417Z'} -
New CVE Received by [email protected]
Jun. 21, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'libexpat project', 'product': 'libexpat', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.8.2', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] Added Description libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219. Added CVSS V3.1 AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Added CWE CWE-416 Added Reference https://github.com/libexpat/libexpat/pull/1278