CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4Description
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, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.
Analysis
A DNS response parsing vulnerability exists in the GNU C Library (glibc) versions 2.34 through 2.43 affecting the gethostbyaddr and gethostbyaddr_r functions. When a malicious or compromised DNS server returns a crafted response that violates the DNS specification, the library may incorrectly treat non-answer sections (such as authority or additional sections) as valid answers, leading to buffer overflow and information disclosure. …
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Remediation
Within 7 days: Identify all affected systems running the GNU C Library and apply vendor patches promptly. Monitor vendor channels for patch availability.
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Priority Score
Vendor Status
Debian
| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | vulnerable | 2.31-13+deb11u11 | - |
| bullseye (security) | vulnerable | 2.31-13+deb11u13 | - |
| bookworm | vulnerable | 2.36-9+deb12u13 | - |
| bookworm (security) | vulnerable | 2.36-9+deb12u7 | - |
| trixie | vulnerable | 2.41-12+deb13u2 | - |
| forky, sid | vulnerable | 2.42-13 | - |
| (unstable) | fixed | (unfixed) | - |
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External POC / Exploit Code
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EUVD-2026-13796