Use After Free in Tex Live
CVE-2026-63729
The SyncTeX parser (synctex_parser.c) shipped with TeX Live and embedded by downstream consumers such as GNOME Evince contains a heap use-after-free vulnerability that allows attackers to crash applications or potentially execute arbitrary code by supplying a malformed .synctex or .synctex.gz file. A malformed SyncTeX file can construct a ref node with a NULL parent pointer, causing the replacement routine to fail to detach the node from its sibling chain, which triggers recursive freeing of live tree nodes and leaves dangling pointers that are later accessed by the parser during document load.
Vulnerability class: Use-After-Free
EPSS: 0.001 (2.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.6 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H.
Affected products
- Tex Live — versions 0, TeX Live 2026
Weakness classification (CWE)
References
- disclosure@vulncheck.com (product)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63729?
- CVE-2026-63729 is a medium-severity vulnerability in Tex Live, classified under Use After Free. CVSS score: 6.6/10. Published 2026-07-21.
- How severe is CVE-2026-63729?
- Medium severity. CVSS v3 base score is 6.6 out of 10.