uclibc — security advisory

{
  "id": "478c48b77041b96615307375ccfde48fed55671b6c87787f64df99dd4dc4fda1",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-43523",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-43523",
    "summary": "In uClibc and uClibc-ng before 1.0.39, incorrect handling of special characters in domain names returned by DNS servers via gethostbyname, getaddrinfo, gethostbyaddr, and getnameinfo can lead to output of wrong hostnames (leading to domain hijacking) or injection into applications (leading to remote code execution, XSS, applications crashes, etc.). In other words, a validation step, which is expected in any stub resolver, does not occur.",
    "evidence": "osv:DEBIAN-CVE-2021-43523",
    "products": [
      {
        "name": {
          "value": "uclibc",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.0.35-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.0.54-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "uclibc",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.0.35-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1.0.54-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "uclibc",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.0.35-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "1.0.54-1",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "DEBIAN-CVE-2021-43523",
      "aliases": [
        "DEBIAN-CVE-2021-43523"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "uclibc",
            "purl": "pkg:deb/debian/uclibc?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "1.0.35-1",
            "1.0.54-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-43523.json"
          },
          "ecosystem_specific": {
            "urgency": "unimportant"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "uclibc",
            "purl": "pkg:deb/debian/uclibc?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "1.0.35-1",
            "1.0.54-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-43523.json"
          },
          "ecosystem_specific": {
            "urgency": "unimportant"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "uclibc",
            "purl": "pkg:deb/debian/uclibc?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "1.0.35-1",
            "1.0.54-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-43523.json"
          },
          "ecosystem_specific": {
            "urgency": "unimportant"
          }
        }
      ],
      "modified": "2026-10-23T18:04:16.827266806Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-43523"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-43523"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-43523",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 423126,
  "published_at": "2021-11-10T15:15:12.213+00:00"
}