{"id":"CVE-2026-4438","summary":"gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames","details":"Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.","modified":"2026-07-01T11:53:20.693263503Z","published":"2026-03-20T19:59:06.064Z","related":["ALSA-2026:19061","ALSA-2026:20597","CGA-6448-55wg-5294","SUSE-SU-2026:1369-1","SUSE-SU-2026:21019-1","SUSE-SU-2026:21039-1","SUSE-SU-2026:21069-1","SUSE-SU-2026:21164-1","openSUSE-SU-2026:10662-1","openSUSE-SU-2026:20501-1"],"database_specific":{"cna_assigner":"glibc","unresolved_ranges":[{"extracted_events":[{"introduced":"2.34"},{"last_affected":"2.43"}],"source":"AFFECTED_FIELD"}],"cwe_ids":["CWE-20"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4438.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4438.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4438"},{"type":"REPORT","url":"https://sourceware.org/bugzilla/show_bug.cgi?id=34015"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://sourceware.org/git/glibc.git","events":[{"introduced":"ae37d06c7d127817ba43850f0f898b793d42aea7"},{"last_affected":"f762ccf84f122d1354f103a151cba8bde797d521"}],"database_specific":{"cpe":"cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"2.34"},{"last_affected":"2.43"}],"source":"CPE_RANGE"}}],"versions":["glibc-2.43","glibc-2.42","glibc-2.42.9000","glibc-2.41.9000","glibc-2.41","glibc-2.40","glibc-2.40.9000","glibc-2.39.9000","glibc-2.39","glibc-2.38","glibc-2.38.9000","glibc-2.37","glibc-2.37.9000","glibc-2.36","glibc-2.36.9000","glibc-2.35","glibc-2.35.9000","glibc-2.34","glibc-2.34.9000"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-4438.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}