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.
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Thu, 17 Sep 2026 19:30:00 +0000
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ssvc
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Thu, 17 Sep 2026 17:00:00 +0000
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| Description | 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. | |
| Title | Assertion failure in the DNS stub resolver with a long search domain | |
| Weaknesses | CWE-617 | |
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cvssV3_1
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Status: PUBLISHED
Assigner: glibc
Published:
Updated: 2026-09-17T18:09:16.072Z
Reserved: 2026-05-15T12:15:59.229Z
Link: CVE-2026-8674
Updated: 2026-09-17T18:09:16.072Z
Status : Received
Published: 2026-09-17T17:16:53.220
Modified: 2026-09-17T19:17:06.427
Link: CVE-2026-8674
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OpenCVE Enrichment
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