CVE-2026-8674Assertion failure in the DNS stub resolver with a long search domain
Updated under an hour ago ()
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It affects The GNU C Library glibc. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Initializing 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.
- CVSS
- 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-617
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- glibc
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
The GNU C Library glibc gnu_c_library:glibc (from the name) | from 2.26 through 2.44 | CNA record |
References
- https://sourceware.org/bugzilla/show_bug.cgi?id=31026issue-tracking
- https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0021vendor-advisory
- https://sourceware.org/git/?p=glibc.git;a=commit;h=506ea57086bfb9ce3daff1c14246a1cb532aba0apatch
- https://joshua.hu/fuzzing-glibc-libresolvtechnical-description
- http://www.openwall.com/lists/oss-security/2026/09/17/4
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.