Vulnerability-Lookup

GHSA-QG52-8PR2-XJ9V

Vulnerability from github – Published: 2026-08-27 21:31 – Updated: 2026-08-28 00:31

Details

Passing an effectively empty string to the ,ccs= syntax extension of the mode argument in the fopen function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled.

This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for ccs should not pass them through without validation.

Severity

4.9 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-18374"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-27T20:17:03Z",
    "severity": "MODERATE"
  },
  "details": "Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled.\n\n\n\nThis usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for `ccs` should not pass them through without validation.",
  "id": "GHSA-qg52-8pr2-xj9v",
  "modified": "2026-08-28T00:31:58Z",
  "published": "2026-08-27T21:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18374"
    },
    {
      "type": "WEB",
      "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=34574"
    },
    {
      "type": "WEB",
      "url": "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0015"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/27/6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-18374 (GCVE-0-2026-18374)

Vulnerability from cvelistv5 – Published: 2026-08-27 19:20 – Updated: 2026-08-27 22:21

Summary

Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled. This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for `ccs` should not pass them through without validation.

Severity

4.9 (Medium)


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

CWE

Buffer overflow in fopen mode argument processing
CWE-787 - Out-of-bounds write

Assigner

glibc redhat root

References

3 references

URL	Tags
https://sourceware.org/bugzilla/show_bug.cgi?id=34574	issue-tracking
https://sourceware.org/git/?p=glibc.git;a=blob_pl…	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/08/27/6

Impacted products

1 product

Vendor	Product	Version
The GNU C Library	glibc	Affected: 0 , < 2.45 (custom)

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JSON

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        "references": [
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          }
        ],
        "title": "CVE Program Container"
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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.

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GHSA-QG52-8PR2-XJ9V

CVE-2026-18374 (GCVE-0-2026-18374)

Tags

Sightings

Nomenclature