VulnSocial

CVE-2026-63729General

LOWCVSS 6.8 · MEDIUM

Exploit discussion active in current signal (1 latest mentions)

Immediate actions

  • Patch affected systems immediately
  • Hunt for exploitation attempts and persistence artifacts
  • Increase monitoring for publicly documented tradecraft

Recommended action window: High priority (within 72h)

NVD 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.

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2.0/ 10 priority

Sources & remediation

Other references
Weakness type (CWE)
CWE-416

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

STABLE

Threat summary

  • Public PoC is present in monitored signal
  • Patch or workaround signal is available
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • PoC mentioned or linked in 1 signal
  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 2 signals
  • General: 1 classified signal
  • Disclosure: 1 classified signal
  • Peaked 1d ago at 1 mentions (2026-07-21); latest day: 1
  • 2 total mentions across 2 days

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-07-21: 1Mentions · 2026-07-22: 1PoC Mentioned / Linked · 2026-07-22: 1Patch / Workaround · 2026-07-22: 1Technical Details · 2026-07-21: 1Technical Details · 2026-07-22: 107-2107-22
Signal classification2 categories
General
150.0%
Disclosure
150.0%
Referenced assets3 URLs
Classification over time
DateTotalLabels
2026-07-211
General1
2026-07-221
Disclosure1
Full discourse2 posts
  • Fatih Çelik@fatihclk01
    Disclosure

    While fuzzing GNOME Evince, I discovered a Use-After-Free (UaF) vulnerability rooted in TeX Live’s SyncTeX parser, tracked as CVE-2026-63729. Since SyncTeX is embedded across various document previewers and TeX tools, downstream applications parsing untrusted SyncTeX files were affected. • Affected: TeX Live versions up to 2025 • Fixed in: TeX Live 2026 Read my blog post here: https://fatihhcelik.github.io/posts/evince-synctex-heap-use-after-free/

    Post summary

    The author reports a new Use-After-Free vulnerability in TeX Live’s SyncTeX parser (CVE-2026-63729), affecting versions up to 2025, with a patch released in TeX Live 2026 and PoC details linked in a blog post.

    0101241.2K
    476 followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    General

    CVE-2026-63729 Heap Use-After-Free Vulnerability in SyncTeX Parser TeX L... https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-63729 Don't wait vulnerability scanning results: https://alerts.vulmon.com/?utm_source=twitter&utm_medium=social&utm_campaign=2102281&utm_content=2

    Post summary

    The tweet references CVE‑2026‑63729, a heap use‑after‑free in SyncTeX’s parser, and links to Vulmon’s details page, but provides no PoC, exploit, patch, or active exploitation evidence.

    00000115
    4.1K followersView on X

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