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glibc — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-33574

The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.

Products
glibc
Affected versions
Not specified
Fixed versions
2.32-1
CVEs
CVE-2021-33574
Confirmed fixed CVEs
Not specified
Updated in this feed
30 Oct 2026, 16:20 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-33574

core-osv · Original source

Published 25 May 2021, 22:15 UTC

The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.

osv:DEBIAN-CVE-2021-33574

glibc

Fixed versions: 2.32-1

glibc

Fixed versions: 2.32-1

glibc

Fixed versions: 2.32-1

Complete source record
{
  "id": "6009a2af27b88d5e264dceb9480e19d528581cd664933b7528b2c66ca2110afd",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-33574",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-33574",
    "summary": "The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.",
    "evidence": "osv:DEBIAN-CVE-2021-33574",
    "products": [
      {
        "name": {
          "value": "glibc",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.32-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "glibc",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.32-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "glibc",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.32-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "DEBIAN-CVE-2021-33574",
      "aliases": [
        "DEBIAN-CVE-2021-33574"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.32-1"
                }
              ]
            }
          ],
          "package": {
            "name": "glibc",
            "purl": "pkg:deb/debian/glibc?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-33574.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.32-1"
                }
              ]
            }
          ],
          "package": {
            "name": "glibc",
            "purl": "pkg:deb/debian/glibc?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-33574.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.32-1"
                }
              ]
            }
          ],
          "package": {
            "name": "glibc",
            "purl": "pkg:deb/debian/glibc?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-33574.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-15T09:47:29.951012914Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-33574"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-33574"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-33574",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 327515,
  "published_at": "2021-05-25T22:15:10.41+00:00"
}