TeX Live SyncTeX Parser Heap Use-After-Free via Malformed SyncTeX File (CVE-2026-63729) | HOL Guard CVE

Medium · CVSS 6.8CVE-2026-63729

TeX Live SyncTeX Parser Heap Use-After-Free via Malformed SyncTeX File

Answer in brief

CVE-2026-63729 records a Medium severity (CVSS 6.8) vulnerability in TeX Live SyncTeX Parser Heap Use-After-Free via Malformed SyncTeX File. The current sources do not mark it as known exploited. The current feed maps TeX Live/TeX Live (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 21, 2026Updated Sep 24, 2026Source checked Sep 24, 2026First seen by HOL Sep 24, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps TeX Live/TeX Live (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
TeX Live/TeX Livegeneric	>=0 <=TeX Live 2025	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for TeX Live/TeX Live.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Jul 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 24, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.