---
id: CVE-2026-8674
title: >-
  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 assert…
summary: >-
  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 assert…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-617
  - CWE-1025
vendor: The GNU C Library
product: glibc
affected:
  - glibc >= 2.26 <= 2.44
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:47.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8674'
references:
  - url: 'https://joshua.hu/fuzzing-glibc-libresolv'
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=31026'
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0021
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://sourceware.org/git/?p=glibc.git;a=commit;h=506ea57086bfb9ce3daff1c14246a1cb532aba0a
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/17/4'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8674.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-8674'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536382'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-8674'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8674'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00306
epssPercentile: 0.23562
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T18:05:54.714741Z'
ingestedAt: '2026-09-17T17:23:30.631Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Hardened Images, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 10, … · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8674.json)