Description
A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.
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 | 1.16.2-1 | — |
| Debian 13 | krb5 | 1.16.2-1 | — |
| Debian 12 | krb5 | 1.16.2-1 | — |
| Debian 9 | krb5 | 1.15-1+deb9u3 | DLA-2771-1 |
| Debian 8 | krb5 | 1.12.1+dfsg-19+deb8u5 | DLA-1643-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | krb5 | 1.19.2-2ubuntu0.1 | USN-5828-1 |
| Ubuntu 20.04 LTS | krb5 | 1.17-6ubuntu4.2 | USN-5828-1 |
| Ubuntu 18.04 LTS | krb5 | 1.16-2ubuntu0.3 | USN-5828-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | krb5 | 1.13.2+dfsg-5ubuntu2.2+esm3 | USN-5828-1 |
| Ubuntu Pro 14.04 LTS | krb5 | 1.12+dfsg-2ubuntu5.4+esm1 | USN-5828-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | krb5 +7 | 1.15.1-37.el7_7.2 | RHBA-2019:2599 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES 12 SP3 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES 12 SP2 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES 12 SP1 | krb5 | 1.12.1-38.13.2 | SUSE-SU-2019:0113-1 |
| SLES 12 | krb5 | 1.12.1-38.13.2 | SUSE-SU-2019:0113-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP4 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES for SAP 12 SP3 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES for SAP 12 SP2 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SLES for SAP 12 SP1 | krb5 | 1.12.1-38.13.2 | SUSE-SU-2019:0113-2 |
| SUSE OpenStack Cloud 7 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
| SUSE Enterprise Storage 4 | krb5 | 1.12.5-40.31.1 | SUSE-SU-2019:0111-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | krb5 | 1.19.2-3.1 | openSUSE-SU-2024:11549-1 |
| openSUSE Leap 15.0 | krb5 +1 | 1.15.2-lp150.5.3.1 | openSUSE-SU-2019:0063-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | krb5 | 1.15.4-r0 | — |
| Alpine v3.23 | krb5 | 1.15.4-r0 | — |
| Alpine v3.22 | krb5 | 1.15.4-r0 | — |
| Alpine v3.21 | krb5 | 1.15.4-r0 | — |
| Alpine v3.20 | krb5 | 1.15.4-r0 | — |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | krb5 | 1.15.4-r0 | — |
| Alpine v3.18 | krb5 | 1.15.4-r0 | — |
| Alpine v3.17 | krb5 | 1.15.4-r0 | — |
| Alpine v3.16 | krb5 | 1.15.4-r0 | — |
| Alpine v3.15 | krb5 | 1.15.4-r0 | — |
| Alpine v3.14 | krb5 | 1.15.4-r0 | — |
| Alpine v3.13 | krb5 | 1.15.4-r0 | — |
| Alpine v3.12 | krb5 | 1.15.4-r0 | — |
| Alpine v3.11 | krb5 | 1.15.4-r0 | — |
| Alpine v3.10 | krb5 | 1.15.4-r0 | — |
| Alpine v3.9 | krb5 | 1.15.4-r0 | — |
| Alpine v3.8 | krb5 | 1.15.4-r0 | — |
| Alpine v3.7 | krb5 | 1.15.4-r0 | — |
| Alpine v3.6 | krb5 | 1.14.3-r3 | — |
Advisories 11
- USN-5828-1 krb5 vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- RHBA-2019:2599 Red Hat Bug Fix Advisory: krb5 bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- DLA-1643-1 krb5 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2771-1 krb5 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11549-1 krb5-1.19.2-3.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0113-1 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0111-1 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:0113-2 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:0063-1 Security update for krb5 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2022-0602 IBM Security Verify Access: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 17, 2024
- WID-SEC-2023-0199 MIT Kerberos: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Jan 25, 2023
References
- FEDORA-2018-7db7ccda4d vendor-advisory
- http://krbdev.mit.edu/rt/Ticket/Display.html?id=8763
- https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086
- [debian-lts-announce] 20190125 [SECURITY] [DLA 1643-1] krb5 security update mailing-list
- https://security.netapp.com/advisory/ntap-20190416-0006/
- [debian-lts-announce] 20210930 [SECURITY] [DLA 2771-1] krb5 security update mailing-list