CVE-2026-63729

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

MEDIUM
6.6
CVSS Score
Published: July 21, 2026 at 01:35 AM UTC
Updated: July 23, 2026 at 09:12 PM UTC
2 products affected across 2 vendorsTex LiveTeX Live

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Severity
MEDIUM6.6
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 2025
v ≤ TeX Live 2025
Vendor states this is fixed in TeX Live 2026 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.6MEDIUMVulnCheck
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-416

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