Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| The GNU C Library | glibc | 2.34 – ≤ 2.43 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | glibc | 2.42-14 | — |
| Debian 13 | glibc | 2.41-12+deb13u3 | — |
| Debian 12 | glibc | 2.36-9+deb12u14 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | glibc | 2.43-2ubuntu2.3 | USN-8611-1 |
| Ubuntu 25.10 | glibc | No fix yet | — |
| Ubuntu 24.04 LTS | glibc | 2.39-0ubuntu8.8 | USN-8611-1 |
| Ubuntu 22.04 LTS | glibc | 2.35-0ubuntu3.14 | USN-8611-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | eglibc | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | glibc +220 | 2.39-121.el10_2 | RHSA-2026:19061 |
| RHEL 9 | nscd +214 | 2.34-270.el9_8 | RHSA-2026:20597 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | glibc +223 | 2.42-11.1.hum1 | RHSA-2026:7316 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | glibc +220 | 2.39-121.el10_2.alma.1 | ALSA-2026:19061 |
| AlmaLinux 9 | nscd +214 | 2.34-270.el9_8 | ALSA-2026:20597 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | glibc | 2.39-121.el10_2 | RLSA-2026:19061 |
| Rocky Linux 9 | glibc | 2.34-270.el9_8 | RLSA-2026:20597 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | glibc | 2.38-150600.14.46.1 | SUSE-SU-2026:1369-1 |
| SLES 15 SP6 | glibc | 2.38-150600.14.46.1 | SUSE-SU-2026:1369-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | glibc | 2.40-160000.4.1 | SUSE-SU-2026:21164-1 |
| SLES for SAP 15 SP6 | glibc | 2.38-150600.14.46.1 | SUSE-SU-2026:1369-1 |
| SLES 16.0 | glibc | 2.40-160000.4.1 | SUSE-SU-2026:21164-1 |
| SLE Micro 6.2 | glibc | 2.40-160000.4.1 | SUSE-SU-2026:21019-1, SUSE-SU-2026:20999-1 |
| SLE Micro 6.1 | glibc | 2.38-slfo.1.1_7.1 | SUSE-SU-2026:21039-1 |
| SLE Micro 6.0 | glibc | 2.38-12.1 | SUSE-SU-2026:21069-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | glibc | 2.43-1.1 | openSUSE-SU-2026:10662-1 |
| openSUSE Leap 16.0 | glibc +4 | 2.40-160000.4.1 | openSUSE-SU-2026:20501-1 |
| openSUSE Leap 15.6 | glibc | 2.38-150600.14.46.1 | SUSE-SU-2026:1369-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | glibc | 2.38-19 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | glibc +220 | 2.39-121.0.1.el10_2 | ELSA-2026-19061 |
| Oracle Linux 9 | nscd +214 | 2.34-270.0.1.el9_8 | ELSA-2026-20597 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | sln +51 | 2.43-r4 | — |
Advisories 24
- ALSA-2026:20597 Moderate: glibc security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:19061 Moderate: glibc security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-0817 GNU libc: Mehrere Schwachstellen ermöglichen Manipulation von DNS Antworten BSI CERT-Bund (WID) · Oct 21, 2026
- WID-SEC-2026-3623 IBM DataPower Gateway: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 18, 2026
- NCSC-2026-0431 Kwetsbaarheden verholpen in IBM DataPower Gateway en onderliggende componenten NCSC-NL (Netherlands) · Oct 16, 2026
- RHSA-2026:7316 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:20597 Red Hat Security Advisory: glibc security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:19061 Red Hat Security Advisory: glibc security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- SSA-082556 SSA-082556: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.5 Siemens ProductCERT · Oct 13, 2026
- VDE-2026-088 METTLER TOLEDO: LabX Standard and Enterprise Report on External Component Analysis - v21.4 CERT@VDE · Sep 10, 2026
- WID-SEC-2026-3038 Meinberg LANTIME: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 26, 2026
- USN-8611-1 glibc vulnerabilities Ubuntu Security Notices (USN) · Jul 27, 2026
- SUSE-SU-2026:20999-1 Security update for glibc SUSE / openSUSE Security Updates · Jul 9, 2026
- ELSA-2026-19061 Moderate: glibc security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 8, 2026
- ELSA-2026-20597 Moderate: glibc security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 23, 2026
- RLSA-2026:20597 Moderate: glibc security update Rocky Linux Security Advisories · May 30, 2026
- RLSA-2026:19061 Moderate: glibc security update Rocky Linux Security Advisories · May 29, 2026
- openSUSE-SU-2026:10662-1 glibc-2.43-1.1 on GA media SUSE / openSUSE Security Updates · May 1, 2026
- openSUSE-SU-2026:20501-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21164-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:1369-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 16, 2026
- SUSE-SU-2026:21069-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 14, 2026
- SUSE-SU-2026:21039-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 14, 2026
- SUSE-SU-2026:21019-1 Security update for glibc SUSE / openSUSE Security Updates · Apr 14, 2026