CVE-2026-4438: medium-severity vulnerability in The GNU C Library glibc
gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.4epss 0.3%
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.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected products
The GNU C Library · glibcRelated CVEs — The GNU C Library glibc
In the same product, most dangerous first.
CVE-2024-2961HIGHCVE-2024-2961EPSS 88.3%CVE-2024-33599HIGHnscd: Stack-based buffer overflow in netgroup cacheEPSS 1.3%CVE-2024-33600MEDIUMnscd: Null pointer crashes after notfound responseEPSS 1.2%CVE-2024-33601HIGHnscd: netgroup cache may terminate daemon on memory allocation failureEPSS 1.1%CVE-2026-0915HIGHgetnetbyaddr and getnetbyaddr_r leak stack contents to DNS resovlerEPSS 0.6%CVE-2025-4802HIGHCVE-2025-4802EPSS 0.6%