Skip to content
Fencer Intel
medium 4.2

CVE-2026-89092 json

Stack overflow in nscd due to unbounded alloca use

published 2mo ago modified 16d ago also EUVD-2026-75897

cvss
4.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

The nscd service in the GNU C Library 2.3.4 onwards may crash due to a stack overflow when a malicious DNS server returns too large a response for a DNS query, resulting in degraded DNS resolution for the system.

Exploitation of this bug needs a system that has nscd enabled and using an untrusted DNS server for name resolution, with the compromised DNS server being capable of processing records large enough to result in a stack overflow in an nscd thread stack.  During experimentation, bind 9 was unable to handle large records, but that could change in future or with a different name server.  In typical installations, nscd is executed in an isolated context as its own user without a shell, due to which any compromise of that service is isolated.

There is a remote possibility of nscd cache corruption if an attacker manages to get the stack pointer into a desired point in the heap, potentially resulting in other caches in nscd being overwritten with corrupt data through the stack overflow, until the buggy code path eventually results in a crash.

Finally, a crash in nscd may result in performance degradation when resolving names, but it does not result in a denial of service.

Patch / fix

  • The GNU C Library glibc 2.45
  • glibc Debian 14 2.43-7

debian advisories DEBIAN-CVE-2026-89092

  • 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 LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.22-114.55.1

suse advisories SUSE-SU-2026:24281-1SUSE-SU-2026:24326-1SUSE-SU-2026:4656-1SUSE-SU-2026:4654-1SUSE-SU-2026:4591-1

  • 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-2026:95618

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

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

Is CVE-2026-89092 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-2026-89092 updated cvss 4.2

glibc: nscd stack overflow leads to degraded DNS resolution

  • 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 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 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 2.34-290.el9_9, glibc-utils 2.34-284.el9_8.4, glibc-locale-source 2.34-290.el9_9, glibc-locale-source 2.34-284.el9_8.4
    fixed: vendor fix RHSA-2026:95618
  • 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 2.34-290.el9_9, glibc 2.34-290.el9_9, libnsl 2.34-290.el9_9, nscd 2.34-284.el9_8.4, glibc 2.34-284.el9_8.4, libnsl 2.34-284.el9_8.4, +8 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nss_db 2.34-290.el9_9, nss_db 2.34-284.el9_8.4, nss_hesiod 2.34-290.el9_9, nss_hesiod 2.34-284.el9_8.4, glibc-benchtests 2.34-290.el9_9, glibc-benchtests 2.34-284.el9_8.4
    fixed: vendor fix RHSA-2026:95618
  • 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 Enterprise Linux 10 glibc Red Hat Hardened Images glibc
    not affected: component not present
show 1 more
  • 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
2mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

Affected products

  • The GNU C Library glibc

Classification

Weakness
  • CWE-789 Memory Allocation with Excessive Size Value

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.