CVE-2026-128241

libexpat xmlwf through 2.10.0 Symlink Following via -d Output Directory

Published Nov 13, 2026 CVSS 4.0 · 4.1 Medium EPSS < 1% KEV · Not listed

Description

The xmlwf tool in libexpat through 2.10.0 contains a symlink following vulnerability because -d output mode opens files with fopen("wb"), which follows symbolic links. Local attackers with write access to the output directory can plant a symlink at the expected output name to truncate or overwrite files writable by the xmlwf user.

Affected Products

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	≤ 2.10.0

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Local

Attack Complexity High

Privileges Required Low

Attack Requirements Present

User Interaction Passive

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.137% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://github.com/libexpat/libexpat
https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1272-L1275
https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1338-L1347
https://github.com/libexpat/libexpat/pull/1502
https://www.vulncheck.com/advisories/libexpat-xmlwf-through-2.10.0-symlink-following-via-d-output-directory

History

Nov 13, 2026 9:45 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		The xmlwf tool in libexpat through 2.10.0 contains a symlink following vulnerability because -d output mode opens files with fopen("wb"), which follows symbolic links. Local attackers with write access to the output directory can plant a symlink at the expected output name to truncate or overwrite files writable by the xmlwf user.
Title		libexpat xmlwf through 2.10.0 Symlink Following via -d Output Directory
First Time appeared		Libexpat Project Libexpat Project libexpat
Weaknesses		CWE-59
CPEs		cpe:2.3:a:libexpat_project:libexpat::::::::
Vendors & Products		Libexpat Project Libexpat Project libexpat
References		https://github.com/libexpat/libexpat https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1272-L1275 https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1338-L1347 https://github.com/libexpat/libexpat/pull/1502 https://www.vulncheck.com/advisories/libexpat-xmlwf-through-2.10.0-symlink-following-via-d-output-directory
Metrics		cvssV3_1 `{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N'}` cvssV4_0 `{'score': 4.1, 'vector': 'CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}`