Skip to content
Fencer Vulns
medium 6.5

CVE-2026-6238 json

Buffer overread in ns_printrrf with corrupted RDATA field

published 2026-04-28 6 mo ago modified 2026-10-15 25 d ago also EUVD-2026-26071

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail to validate the RDATA content against the RDATA length in a DNS response when processing A6, CERT, LOC, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory.

These functions are for application debugging only and hence not in the path of code executed by the DNS resolver. Further, they have been deprecated since version 2.34 and should not be used by any new applications. Applications should consider porting away from these interfaces since they may be removed in future versions.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.6
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.6
  • glibc Debian 14 2.43-3

debian advisories DEBIAN-CVE-2026-6238

  • glibc Ubuntu 22.04 LTS 2.35-0ubuntu3.14
  • glibc Ubuntu 24.04 LTS 2.39-0ubuntu8.8
  • glibc Ubuntu 26.04 LTS 2.43-2ubuntu2.3

ubuntu advisories UBUNTU-CVE-2026-6238

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • glibc RHEL 9 2.34-274.el9_8
  • nscd RHEL 9 2.34-274.el9_8
  • libnsl RHEL 9 2.34-274.el9_8
  • nss_db RHEL 9 2.34-274.el9_8
  • nss_hesiod RHEL 9 2.34-274.el9_8
  • glibc-utils RHEL 9 2.34-274.el9_8
  • glibc-common RHEL 9 2.34-274.el9_8
  • glibc-benchtests RHEL 9 2.34-274.el9_8

red hat advisories RHSA-2026:42952RHSA-2026:42733RHSA-2026:42694RHSA-2026:12740

  • glibc SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 +1 more 2.38-150600.14.52.1
  • glibc SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 2.31-150300.104.1
  • glibc Linux Micro 6.0 2.38-14.1
  • glibc Linux Micro Extras 6.2 2.40-160000.6.1
  • glibc Linux Micro 6.1 2.38-slfo.1.1_9.1
  • glibc SLES LTSS Extended Security 12 SP5 2.22-114.49.1

suse advisories SUSE-SU-2026:3030-1SUSE-SU-2026:3029-1SUSE-SU-2026:2987-1SUSE-SU-2026:22523-1SUSE-SU-2026:22538-1SUSE-SU-2026:22453-1

  • glibc openSUSE Leap 16.0 2.40-160000.6.1
  • glibc-cross-s390x-src openSUSE Leap 16.0 2.40-160000.6.1
  • glibc-cross-aarch64-src openSUSE Leap 16.0 2.40-160000.6.1
  • glibc-cross-ppc64le-src openSUSE Leap 16.0 2.40-160000.6.1
  • glibc-cross-riscv64-src openSUSE Leap 16.0 2.40-160000.6.1
  • glibc openSUSE Tumbleweed 2.43-4.1

opensuse advisories openSUSE-SU-2026:21228-1openSUSE-SU-2026:11140-1

  • glibc AlmaLinux 10 2.39-128.el10_2.alma.1
  • libnsl AlmaLinux 10 2.39-128.el10_2.alma.1
  • nss_db AlmaLinux 10 2.39-128.el10_2.alma.1
  • nss_hesiod AlmaLinux 10 2.39-128.el10_2.alma.1
  • glibc-utils AlmaLinux 10 2.39-128.el10_2.alma.1
  • glibc-common AlmaLinux 10 2.39-128.el10_2.alma.1
  • glibc-benchtests AlmaLinux 10 2.39-128.el10_2.alma.1
  • glibc-gconv-extra AlmaLinux 10 2.39-128.el10_2.alma.1

almalinux advisories ALSA-2026:42694ALSA-2026:42733ALSA-2026:42952

  • glibc Rocky Linux 9 2.34-274.el9_8
  • glibc Rocky Linux 10 2.39-128.el10_2
  • glibc Rocky Linux 8 2.28-251.el8_10.40

rocky linux advisories RLSA-2026:42952RLSA-2026:42694RLSA-2026:42733

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-2026-6238 updated cvss 6.5

glibc: glibc: Application crash or uninitialized memory read via crafted DNS response

  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 cert-manager/cert-manager-operator-rhel9 1791788287, cert-manager/jetstack-cert-manager-rhel9 1791371069, cert-manager/cert-manager-istio-csr-rhel9 1791378395, cert-manager/cert-manager-operator-bundle 1791970484, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791371080
    fixed: vendor fix RHSA-2026:82336
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-operator-rhel9 1790272426, cert-manager/cert-manager-operator-rhel9 1790589855, cert-manager/jetstack-cert-manager-rhel9 1790223279, cert-manager/jetstack-cert-manager-rhel9 1790589912, cert-manager/cert-manager-istio-csr-rhel9 1790223719, cert-manager/cert-manager-istio-csr-rhel9 1790589914, +2 more
    fixed: vendor fix RHSA-2026:72475
  • Red Hat Cost Management 4 costmanagement/costmanagement-metrics-rhel9-operator 1790844333
    fixed: vendor fix RHSA-2026:81201
  • Red Hat Discovery 2 discovery/discovery-server-rhel9 1784821670
    fixed: vendor fix RHSA-2026:46836
  • Red Hat Enterprise Linux AppStream (v. 8) glibc-utils 2.28-251.el8_10.40, compat-libpthread-nonshared 2.28-251.el8_10.40
    fixed: vendor fix RHSA-2026:42733
  • Red Hat Enterprise Linux AppStream (v. 9) glibc-utils 2.34-274.el9_8, glibc-locale-source 2.34-274.el9_8
    fixed: vendor fix RHSA-2026:42952
  • Red Hat Enterprise Linux AppStream (v. 10) glibc-utils 2.39-128.el10_2, glibc-locale-source 2.39-128.el10_2
    fixed: vendor fix RHSA-2026:42694
show 11 more
  • Red Hat Enterprise Linux BaseOS (v. 8) nscd 2.28-251.el8_10.40, glibc 2.28-251.el8_10.40, libnsl 2.28-251.el8_10.40, nss_db 2.28-251.el8_10.40, glibc-common 2.28-251.el8_10.40, glibc-gconv-extra 2.28-251.el8_10.40, +3 more
    fixed: vendor fix RHSA-2026:42733
  • Red Hat Enterprise Linux BaseOS (v. 9) nscd 2.34-274.el9_8, glibc 2.34-274.el9_8, libnsl 2.34-274.el9_8, glibc-common 2.34-274.el9_8, glibc-gconv-extra 2.34-274.el9_8, glibc-all-langpacks 2.34-274.el9_8, +1 more
    fixed: vendor fix RHSA-2026:42952
  • Red Hat Enterprise Linux BaseOS (v. 10) glibc 2.39-128.el10_2, libnsl 2.39-128.el10_2, glibc-common 2.39-128.el10_2, glibc-gconv-extra 2.39-128.el10_2, glibc-all-langpacks 2.39-128.el10_2, glibc-minimal-langpack 2.39-128.el10_2
    fixed: vendor fix RHSA-2026:42694
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nss_db 2.34-274.el9_8, nss_hesiod 2.34-274.el9_8, glibc-benchtests 2.34-274.el9_8
    fixed: vendor fix RHSA-2026:42952
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nss_db 2.39-128.el10_2, nss_hesiod 2.39-128.el10_2, glibc-benchtests 2.39-128.el10_2
    fixed: vendor fix RHSA-2026:42694
  • Red Hat Enterprise Linux CRB (v. 8) nss_hesiod 2.28-251.el8_10.40, glibc-benchtests 2.28-251.el8_10.40
    fixed: vendor fix RHSA-2026:42733
  • Red Hat Hardened Images glibc 2.42-12.hum1, glibc32 2.42-12.hum1, glibc-utils 2.42-12.hum1, glibc-common 2.42-12.hum1, glibc-benchtests 2.42-12.hum1, glibc-gconv-extra 2.42-12.hum1, +5 more
    fixed: vendor fix RHSA-2026:12740
  • Red Hat Insights proxy 1.5 insights-proxy/insights-proxy-container-rhel9 1786433656
    fixed: vendor fix RHSA-2026:53371
  • Red Hat OpenShift distributed tracing 3.10.1 rhosdt/tempo-rhel9 1784775768, rhosdt/tempo-query-rhel9 1784775793, rhosdt/tempo-gateway-rhel9 1784775770, rhosdt/tempo-rhel9-operator 1784775782, rhosdt/tempo-operator-bundle 1784777166, rhosdt/tempo-gateway-opa-rhel9 1784775772, +1 more
    fixed: vendor fix RHSA-2026:44624
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1784794778, rhui5/rhua-rhel9 1784795076, rhui5/haproxy-rhel9 1784795112, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1784794289, rhui5/installer-tp-rhel9 1787135742, +2 more
    fixed: vendor fix RHSA-2026:44481
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/jetstack-cert-manager-acmesolver-rhel9 1790223630 Red Hat Cost Management 4 costmanagement/costmanagement-metrics-operator-bundle 1790851152 Red Hat Discovery 2 discovery/discovery-ui-rhel9 1784821750 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 Hardened Images libnsl 2.42-12.hum1, nss_db 2.42-12.hum1, nss_hesiod 2.42-12.hum1, compat-libpthread-nonshared 2.42-12.hum1
    +3 more products
    Red Hat OpenShift AI (RHOAI) rhoai/odh-llama-stack-k8s-operator-rhel9 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206
    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
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

Affected products

  • The GNU C Library glibc
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

References

Sources

Fencer Vulns 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.