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TI-2026-03848 Aliases CVE-2026-4437GHSA-m5wq-r4r4-4qrh

gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

Priority LOW 39CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 14 fixed, 4 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-125 and the CVSS impact.

Summary

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00345 28th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 16 advisoriesRed Hat: 14 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
GNUglibc2.34 – 2.43—No fix listedCNA
  • glibc VendorGNU Affected 2.34 – 2.43 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*2.34 – 2.43VulnerableGNU
  • cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:* Versions 2.34 – 2.43 Vulnerable ·GNU

Remediation

Red Hat 16 advisories

  • RHSA-2026:82888 Released 2026-10-14 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.17.2
    • Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/cert-manager-operator-bundle
  • RHSA-2026:82857 Released 2026-10-14 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-bundle
  • RHSA-2026:82372 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
Show 13 more Red Hat advisories
  • RHSA-2026:82354 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-istio-csr-rhel9
  • RHSA-2026:82347 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
  • RHSA-2026:82322 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.17.2
    • Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
  • RHSA-2026:82304 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.17.2
    • Cert Manager support for Red Hat OpenShift release 1.17 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
  • RHSA-2026:72502 Released 2026-09-28 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.20.1
    • Cert Manager support for Red Hat OpenShift release 1.20 registry.redhat.io/cert-manager/cert-manager-trust-manager-rhel9
  • RHSA-2026:58981 Released 2026-08-24 · Red Hat rating Critical
    Red Hat Update Infrastructure 5.3 Technology Preview security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-kubernetes-tp-rhel9, registry.redhat.io/rhui5/installer-tp-rhel9, registry.redhat.io/rhui5/rhua-tp-rhel9
  • RHSA-2026:29197 Released 2026-06-24 · Red Hat rating Important
    A Subscription Management tool for finding and reporting Red Hat product usage
    • Red Hat Discovery 2 registry.redhat.io/discovery/discovery-server-rhel9, registry.redhat.io/discovery/discovery-ui-rhel9
  • RHSA-2026:27998 Released 2026-06-22 · Red Hat rating Important
    Cost Management Metrics Operator Update
    • Cost Management 4 registry.redhat.io/costmanagement/costmanagement-metrics-rhel9-operator
  • RHSA-2026:26319 Released 2026-06-16 · Red Hat rating Important
    Red Hat Update Infrastructure 5.2 security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
  • RHSA-2026:22634 Released 2026-06-02 · Red Hat rating Important
    Insights proxy Container Image
    • Red Hat Insights proxy 1.5 registry.redhat.io/insights-proxy/insights-proxy-container-rhel9
  • RHSA-2026:20597 Released 2026-05-26 · Red Hat rating Moderate
    glibc security update
    • Red Hat Enterprise Linux AppStream (v. 9) glibc-devel-2.34-270.el9_8, glibc-doc-2.34-270.el9_8, glibc-headers-2.34-270.el9_8 +2
    • Red Hat Enterprise Linux BaseOS (v. 9) glibc-2.34-270.el9_8, glibc-all-langpacks-2.34-270.el9_8, glibc-common-2.34-270.el9_8 +47
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) glibc-benchtests-2.34-270.el9_8, glibc-nss-devel-2.34-270.el9_8, glibc-static-2.34-270.el9_8 +2
  • RHSA-2026:19061 Released 2026-05-19 · Red Hat rating Moderate
    glibc security update
    • Red Hat Enterprise Linux AppStream (v. 10) glibc-devel-2.39-121.el10_2, glibc-doc-2.39-121.el10_2, glibc-locale-source-2.39-121.el10_2 +1
    • Red Hat Enterprise Linux BaseOS (v. 10) glibc-2.39-121.el10_2, glibc-all-langpacks-2.39-121.el10_2, glibc-common-2.39-121.el10_2 +47
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) glibc-benchtests-2.39-121.el10_2, glibc-nss-devel-2.39-121.el10_2, glibc-static-2.39-121.el10_2 +2
  • RHSA-2026:7316 Released 2026-04-09 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images glibc-2.42-11.1.hum1@aarch64, glibc-2.42-11.1.hum1@src, glibc-2.42-11.1.hum1@x86_64 +47

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Cert Manager support for Red Hat OpenShift release 1.17Fixed RHSA-2026:82304, RHSA-2026:82322, RHSA-2026:82888
Cert Manager support for Red Hat OpenShift release 1.18Fixed RHSA-2026:82347, RHSA-2026:82354, RHSA-2026:82372, RHSA-2026:82857
Cert Manager support for Red Hat OpenShift release 1.20Fixed RHSA-2026:72502
Cost Management 4Fixed RHSA-2026:27998
Red Hat Discovery 2Fixed RHSA-2026:29197
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:19061
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:20597
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:19061
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:20597
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:19061
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:20597
Red Hat Hardened ImagesFixed RHSA-2026:7316
Red Hat Insights proxy 1.5Fixed RHSA-2026:22634
Red Hat Update Infrastructure 5Fixed RHSA-2026:26319, RHSA-2026:58981
Not affected: 3 products
  • Cost Management 4
  • Red Hat Hardened Images
  • Red Hat Update Infrastructure 5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-4437
  2. 2026-10-03 Alias added: GHSA-m5wq-r4r4-4qrh
  3. 2026-10-14 Fix available: RHSA-2026:82304 · Red Hat
  4. 2026-10-14 Fix available: RHSA-2026:82322 · Red Hat
  5. 2026-10-14 Fix available: RHSA-2026:82372 · Red Hat
  6. 2026-10-14 Fix available: RHSA-2026:82354 · Red Hat
  7. 2026-10-14 Fix available: RHSA-2026:82347 · Red Hat
  8. 2026-10-15 Fix available: RHSA-2026:82857 · Red Hat
  9. 2026-10-15 Fix available: RHSA-2026:82888 · Red Hat
  10. 2026-10-16 Fix available: Cert Manager support for Red Hat OpenShift release 1.17, Cert Manager support for Red Hat OpenShift release 1.18 · Red Hat

References

Exploit 1

  • TI-2023-04522 Glibc: buffer overflow in ld.so leading to privilege escalation KEVCVSS 3.1HIGH 7.8
  • TI-2015-00205 Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and… CVSS 2.0HIGH 10.0
  • TI-2026-04772 scanf %mc off-by-one heap buffer overflow CVSS 3.1CRITICAL 9.8
  • TI-2022-07360 The deprecated compatibility function clnt_create in the sunrpc module of the GNU C… CVSS 3.1CRITICAL 9.8
  • TI-2022-07359 The deprecated compatibility function svcunix_create in the sunrpc module of the GNU C… CVSS 3.1CRITICAL 9.8
  • TI-2015-06274 Multiple stack-based buffer overflows in the (1) send_dg and (2) send_vc functions in the… CVSS 3.0HIGH 8.1
See all 162 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences