Vulnerability-Lookup

UBUNTU-CVE-2026-63729 (CVE-2026-63729)

Vulnerability from osv_ubuntu – Published: 2026-07-21 03:16 – Updated: 2026-07-29 07:59 – Source website

Details

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.

Severity

6.6 (Medium)


                    
                      CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

6.8 (Medium)


                    
                      CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-63729	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-63729	REPORT
	https://fatihhcelik.github.io/posts/evince-syncte…	REPORT

JSON

To clipboard

{
  "affected": [
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            "binary_version": "2015.20160222.37495-1ubuntu0.1+esm1"
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      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2026-63729",
  "modified": "2026-07-29T07:59:18Z",
  "published": "2026-07-21T03:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-63729"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63729"
    },
    {
      "type": "REPORT",
      "url": "https://fatihhcelik.github.io/posts/evince-synctex-heap-use-after-free/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-63729"
  ]
}

CVE-2026-63729 (GCVE-0-2026-63729)

Vulnerability from cvelistv5 – Published: 2026-07-21 01:35 – Updated: 2026-07-28 01:05

Title

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

Summary

Severity

6.8 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

6.6 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-21 13:18 UTC

CWE

CWE-416 - Use After Free

Assigner

VulnCheck mitre root

References

4 references

URL	Tags
https://github.com/TeX-Live/texlive-source/	product
https://github.com/TeX-Live/texlive-source/commit…	patch
https://fatihhcelik.github.io/posts/evince-syncte…
https://www.vulncheck.com/advisories/tex-live-syn…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
TeX Live	TeX Live	Affected: 0 , ≤ TeX Live 2025 (custom) Unaffected: TeX Live 2026 (custom) cpe:2.3:a:tug:tex_live::::::::

Date Public

2026-07-20 00:00

Credits

Fatih Çelik

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.