Description
The AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos 5 (aka krb5) 1.5.2 and later allows remote attackers to cause a denial of service (memory exhaustion in kadmind) by sending repeated failed AUTH_GSSAPI_INIT requests. Each failed request allocates client state that is only freed after a 15-minute expiration timeout, allowing an attacker to accumulate memory faster than it is reclaimed.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 10.2 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Enterprise Linux 9.8 Extended Update Support | — | — |
| Red Hat | Red Hat Hardened Images | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
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 | krb5 | No fix yet | — |
| Debian 13 | krb5 | No fix yet | — |
| Debian 12 | krb5 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | krb5 | No fix yet | — |
| Ubuntu 26.04 LTS | krb5 | No fix yet | — |
| Ubuntu 24.04 LTS | krb5 | No fix yet | — |
| Ubuntu 22.04 LTS | krb5 | No fix yet | — |
| Ubuntu 20.04 LTS | krb5 | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | krb5 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | krb5 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | krb5 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | krb5 +8 | 1.21.1-10.el9_9.2 | RHSA-2026:99715 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.2 EUS | krb5 +8 | 1.21.3-10.el10_2.2 | RHSA-2026:99625 |
| RHEL 9.8 EUS | krb5 +8 | 1.21.1-10.el9_8.3 | RHSA-2026:99716 |
| Red Hat Hardened Images 1 | krb5 +9 | 1.22.3-0.1.hum1 | RHSA-2026:97811 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | libkadm5 +7 | 1.21.3-11.el10_3.2 | RLSA-2026:99624 |
| Rocky Linux 9 | libkadm5 +7 | 1.21.1-10.el9_9.2 | RLSA-2026:99715 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | krb5 | 1.22.3-r0 | — |
| Alpine v3.23 | krb5 | 1.22.3-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | krb5 | No fix yet | — |
Advisories 7
- RHSA-2026:99625 Red Hat Security Advisory: krb5 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:97811 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:99716 Red Hat Security Advisory: krb5 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:99715 Red Hat Security Advisory: krb5 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RLSA-2026:99715 Important: krb5 security, bug fix, and enhancement update Rocky Linux Security Advisories · Nov 13, 2026
- RLSA-2026:99624 Important: krb5 security, bug fix, and enhancement update Rocky Linux Security Advisories · Nov 13, 2026
- WID-SEC-2026-4435 MIT Kerberos: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
References
- RHSA-2026:97811 vendor-advisory
- RHSA-2026:99624 vendor-advisory
- RHSA-2026:99625 vendor-advisory
- RHSA-2026:99715 vendor-advisory
- RHSA-2026:99716 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-112323 vdb-entry
- RHBZ#2478440 issue-tracking