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CVE-2026-4438
gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames
Medium5.4EPSS 0.31%
- Published
- Updated
- Reserved
- Assigned by
- glibc
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium5.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.31% · top 76% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.
Weakness
Affected products
- affected 2.34 – ≤ 2.43
References (2)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2026-4438)Record last updated .