Vulnerability-Lookup

GHSA-H67Q-H62W-5MJR

Vulnerability from github – Published: 2026-06-29 15:32 – Updated: 2026-06-30 21:31

Details

libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. By supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame. Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process.

This issue has been fixed in the commit c2e233fc.

NOTE: The maintainers of this project did not agree that this issue is a vulnerability and considered it a bug.

Severity

7.8 (High)


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

1.8 (Low)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-11979"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-121"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-29T14:16:40Z",
    "severity": "LOW"
  },
  "details": "libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking.\nBy supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame.\nSuccessful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process.\n\nThis issue has been fixed in the commit c2e233fc.\n\nNOTE:\nThe maintainers of this project did not agree that this issue is a vulnerability and considered it a bug.",
  "id": "GHSA-h67q-h62w-5mjr",
  "modified": "2026-06-30T21:31:38Z",
  "published": "2026-06-29T15:32:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11979"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/06/CVE-2026-11979"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/libxml2/-/commit/c2e233fc1b341685fc99621b2768b503f777a72e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-11979 (GCVE-0-2026-11979)

Vulnerability from cvelistv5 – Published: 2026-06-29 13:21 – Updated: 2026-06-29 13:59 X_Open Source Disputed

Title

Stack-Based Buffer Overflow in libxml2

Summary

Severity

1.8 (Low)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-29 13:59 UTC

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

CERT-PL ENISA root

References

2 references

URL	Tags
https://cert.pl/en/posts/2026/06/CVE-2026-11979	third-party-advisory
https://gitlab.gnome.org/GNOME/libxml2/-/commit/c…	patch

Impacted products

1 product

Vendor	Product	Version
xmlsoft	libxml2	Affected: 0 , ≤ 2.15.3 (custom)

Credits

Michał Majchrowicz (AFINE Team) Marcin Wyczechowski (AFINE Team)

Show details on NVD website

JSON

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                "timestamp": "2026-06-29T13:59:12.311421Z",
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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.

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