Description
An authentication bypass flaw was found in the way krb5's certauth interface before 1.16.1 handled the validation of client certificates. A remote attacker able to communicate with the KDC could potentially use this flaw to impersonate arbitrary principals under rare and erroneous circumstances.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| MIT | krb5 | 1.16.1 | — |
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.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | krb5 +7 | 1.15.1-18.el7 | RHSA-2018:0666 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | krb5 | 1.12.1-38.5.3 | SUSE-SU-2018:1425-1 |
| SLES 12 | krb5 | 1.12.1-38.5.3 | SUSE-SU-2018:1425-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | krb5 | 1.12.1-38.5.3 | SUSE-SU-2018:1425-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libkadm5 +6 | 1.15.1-19.amzn2.0.1 | ALAS2-2018-1010 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | libkadm5 +6 | 1.15.1-18.el7 | ELSA-2018-0666 |
Advisories 4
- RHSA-2018:0666 Red Hat Security Advisory: krb5 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- SUSE-SU-2018:1425-1 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2018-1010 Moderate: krb5 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 10, 2018
- ELSA-2018-0666 Moderate: krb5 security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 16, 2018
References
- https://github.com/krb5/krb5/pull/694/commits/50fe4074f188c2d4da0c421e96553acea8378db2
- 100511 vdb-entry
- https://github.com/krb5/krb5/pull/694/commits/1de6ca2f2eb1fdbab51f1549a25a6903aefcc196
- https://github.com/krb5/krb5/pull/694
- RHSA-2018:0666 vendor-advisory
- https://github.com/krb5/krb5/pull/694/commits/b7af544e50a4d8291524f590e20dd44430bf627d
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7562