Description
The kdcpreauth modules in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.2 do not properly track whether a client's request has been validated, which allows remote attackers to bypass an intended preauthentication requirement by providing (1) zero bytes of data or (2) an arbitrary realm name, related to plugins/preauth/otp/main.c and plugins/preauth/pkinit/pkinit_srv.c.
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 | 1.12.1+dfsg-20 | — |
| Debian 13 | krb5 | 1.12.1+dfsg-20 | — |
| Debian 12 | krb5 | 1.12.1+dfsg-20 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | krb5 | 1.12+dfsg-2ubuntu5.2 | USN-2810-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | krb5 +6 | 1.13.2-10.el7 | RHSA-2015:2154 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 | krb5 | 1.12.1-16.1 | SUSE-SU-2015:1276-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 | krb5 | 1.12.1-16.1 | SUSE-SU-2015:1276-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | krb5 | 1.15-1.1 | openSUSE-SU-2024:10004-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | krb5-libs +5 | 1.13.2-10.el7 | ELSA-2015-2154 |
Advisories 5
- RHSA-2015:2154 Red Hat Security Advisory: krb5 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- USN-2810-1 krb5 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- openSUSE-SU-2024:10004-1 krb5-1.15-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:1276-1 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2015-2154 Moderate: krb5 security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 23, 2015