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Fencer Intel
medium 5.3

CVE-2026-8674 json

Assertion failure in the DNS stub resolver with a long search domain

published last mo. modified last mo. also EUVD-2026-82326

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

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 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.

Patch / fix

  • glibc Debian 14 2.43-6

debian advisories DEBIAN-CVE-2026-8674

  • glibc RHEL 10.2 2.39-145.el10_2
  • libnsl RHEL 10.2 2.39-145.el10_2
  • nss_db RHEL 10.2 2.39-145.el10_2
  • nss_hesiod RHEL 10.2 2.39-145.el10_2
  • glibc-utils RHEL 10.2 2.39-145.el10_2
  • glibc-common RHEL 10.2 2.39-145.el10_2
  • glibc-benchtests RHEL 10.2 2.39-145.el10_2
  • glibc-gconv-extra RHEL 10.2 2.39-145.el10_2

red hat advisories RHSA-2026:84753RHSA-2026:69276

  • glibc Linux Micro 6.1 2.38-slfo.1.1_11.1
  • glibc Linux Micro 6.0 2.38-159998.1.1
  • glibc SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 +1 more 2.38-150600.14.61.1
  • glibc SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 2.31-150300.109.1
  • glibc SLES 16.0, Linux Micro Extras 6.2, Linux Micro 6.2 +1 more 2.40-160000.7.1

suse advisories SUSE-SU-2026:24281-1SUSE-SU-2026:24326-1SUSE-SU-2026:4656-1SUSE-SU-2026:4591-1SUSE-SU-2026:23934-1SUSE-SU-2026:23957-1

  • glibc openSUSE Tumbleweed 2.44-3.1
  • glibc openSUSE Leap 16.0 2.40-160000.7.1
  • glibc-cross-s390x-src openSUSE Leap 16.0 2.40-160000.7.1
  • glibc-cross-aarch64-src openSUSE Leap 16.0 2.40-160000.7.1
  • glibc-cross-ppc64le-src openSUSE Leap 16.0 2.40-160000.7.1
  • glibc-cross-riscv64-src openSUSE Leap 16.0 2.40-160000.7.1

opensuse advisories openSUSE-SU-2026:12072-1openSUSE-SU-2026:21968-1

  • glibc AlmaLinux 8 2.28-251.el8_10.53
  • nscd AlmaLinux 8 2.28-251.el8_10.53
  • libnsl AlmaLinux 8 2.28-251.el8_10.53
  • nss_db AlmaLinux 8 2.28-251.el8_10.53
  • nss_hesiod AlmaLinux 8 2.28-251.el8_10.53
  • glibc-utils AlmaLinux 8 2.28-251.el8_10.53
  • glibc-common AlmaLinux 8 2.28-251.el8_10.53
  • glibc-benchtests AlmaLinux 8 2.28-251.el8_10.53

almalinux advisories ALSA-2026:96087ALSA-2026:95618ALSA-2026:84753

  • glibc Rocky Linux 8 2.28-251.el8_10.53
  • glibc Rocky Linux 9 2.34-284.el9_8.4
  • glibc Rocky Linux 10 2.39-145.el10_2

rocky linux advisories RLSA-2026:96087RLSA-2026:95618RLSA-2026:84753

Is CVE-2026-8674 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-8674 updated cvss 5.3

glibc: glibc DNS stub resolver: Denial of Service via long search domain in configuration

  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-core-bff-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +6 more
    under investigation
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1792605272
    fixed: vendor fix RHSA-2026:87400
  • Red Hat Enterprise Linux AppStream (v. 8) glibc-utils 2.28-251.el8_10.53, compat-libpthread-nonshared 2.28-251.el8_10.53
    fixed: vendor fix RHSA-2026:96087
  • Red Hat Enterprise Linux AppStream (v. 9) glibc-utils 2.34-284.el9_8.4, glibc-locale-source 2.34-284.el9_8.4
    fixed: vendor fix RHSA-2026:95618
  • Red Hat Enterprise Linux AppStream (v. 10) glibc-utils 2.39-145.el10_2, glibc-locale-source 2.39-145.el10_2
    fixed: vendor fix RHSA-2026:84753
  • Red Hat Enterprise Linux BaseOS (v. 8) nscd 2.28-251.el8_10.53, glibc 2.28-251.el8_10.53, libnsl 2.28-251.el8_10.53, nss_db 2.28-251.el8_10.53, glibc-common 2.28-251.el8_10.53, glibc-gconv-extra 2.28-251.el8_10.53, +3 more
    fixed: vendor fix RHSA-2026:96087
  • Red Hat Enterprise Linux BaseOS (v. 9) nscd 2.34-284.el9_8.4, glibc 2.34-284.el9_8.4, libnsl 2.34-284.el9_8.4, glibc-common 2.34-284.el9_8.4, glibc-gconv-extra 2.34-284.el9_8.4, glibc-all-langpacks 2.34-284.el9_8.4, +1 more
    fixed: vendor fix RHSA-2026:95618
show 6 more
  • Red Hat Enterprise Linux BaseOS (v. 10) glibc 2.39-145.el10_2, libnsl 2.39-145.el10_2, glibc-common 2.39-145.el10_2, glibc-gconv-extra 2.39-145.el10_2, glibc-all-langpacks 2.39-145.el10_2, glibc-minimal-langpack 2.39-145.el10_2
    fixed: vendor fix RHSA-2026:84753
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nss_db 2.34-284.el9_8.4, nss_hesiod 2.34-284.el9_8.4, glibc-benchtests 2.34-284.el9_8.4
    fixed: vendor fix RHSA-2026:95618
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nss_db 2.39-145.el10_2, nss_hesiod 2.39-145.el10_2, glibc-benchtests 2.39-145.el10_2
    fixed: vendor fix RHSA-2026:84753
  • Red Hat Enterprise Linux CRB (v. 8) nss_hesiod 2.28-251.el8_10.53, glibc-benchtests 2.28-251.el8_10.53
    fixed: vendor fix RHSA-2026:96087
  • Red Hat Hardened Images glibc 2.43-8.6.hum1, libnsl 2.43-8.6.hum1, nss_db 2.43-8.6.hum1, glibc32 2.43-8.6.hum1, nss_hesiod 2.43-8.6.hum1, glibc-utils 2.43-8.6.hum1, +9 more
    fixed: vendor fix RHSA-2026:69276
  • Red Hat Enterprise Linux 6 nscd, glibc, glibc-utils, compat-glibc, glibc-common Red Hat Enterprise Linux 7 nscd, glibc, glibc-utils, compat-glibc, glibc-common Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-kube-rbac-proxy-rhel9, rhoai/odh-maas-controller-rhel9, rhoai/odh-mlflow-operator-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-ogx-k8s-operator-rhel9, +14 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • The GNU C Library glibc

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.