CVE-2026-8674

NameCVE-2026-8674
DescriptionInitializing the DNS stub resolver from an /etc/resolv.conf file, or a LOCALDOMAIN environment variable, whose search list contains a domain of roughly 200 characters or more in the GNU C Library version 2.26 to 2.44 results in an assertion failure which aborts the process. The resolver truncates the search list when copying it into the fixed-size _res.defdname buffer, then asserts that the copy is consistent with the full configuration. The consistency check compared against the wrong size and did not handle a first entry that does not fit, so a correctly truncated list failed the assertion. Any process that resolves names through the library is affected, including long-running processes that reload /etc/resolv.conf on the next query after it changes. Search domains are commonly written to /etc/resolv.conf from data received over DHCP or from a VPN server, so an attacker on the local network may be able to trigger this without privileges on the target system, subject to validation by the network configuration software.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1148168

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
glibc (PTS)bookworm2.36-9+deb12u14vulnerable
bookworm (security)2.36-9+deb12u7vulnerable
trixie2.41-12+deb13u4vulnerable
forky2.43-6fixed
sid2.43-7fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
glibcsource(unstable)2.43-61148168

Notes

[trixie] - glibc <no-dsa> (Minor issue)
[bookworm] - glibc <postponed> (Minor issue, DoS)
https://www.openwall.com/lists/oss-security/2026/09/17/4
https://sourceware.org/git/?p=glibc.git;a=blob;f=advisories/GLIBC-SA-2026-0021
Fixed by: https://sourceware.org/git/?p=glibc.git;a=commit;h=506ea57086bfb9ce3daff1c14246a1cb532aba0a

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