CVE-2026-128241
libexpat xmlwf through 2.10.0 Symlink Following via -d Output Directory
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.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| libexpat libexpat project libexpat/libexpat
github |
≥ 0; ≤ 2.10.0 (affected, semver)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 4.1 medium |
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 | CNA: VulnCheck |
| 3.1 / 4.4 medium |
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N | CNA: VulnCheck |
| 4.0 / 4.1 medium |
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
| 3.1 / 4.4 medium |
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/libexpat/libexpat/pull/1502CNA: VulnCheck · patch, issue-tracking
- https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1272-L1275CNA: VulnCheck · technical-description
- https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1338-L1347CNA: VulnCheck · technical-description
- https://github.com/libexpat/libexpatCNA: VulnCheck · product
- https://www.vulncheck.com/advisories/libexpat-xmlwf-through-2.10.0-symlink-following-via-d-output-directoryCNA: VulnCheck · third-party-advisory
- https://github.com/libexpat/libexpat[email protected]
- https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1272-L1275[email protected]
- https://github.com/libexpat/libexpat/blob/R_2_10_0/expat/xmlwf/xmlwf.c#L1338-L1347[email protected]
- https://github.com/libexpat/libexpat/pull/1502[email protected]
- https://www.vulncheck.com/advisories/libexpat-xmlwf-through-2.10.0-symlink-following-via-d-output-directory[email protected]
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