PatchTheCVEkerberos 5 vulnerabilities and fixes
Recent CVEs affecting kerberos 5, with upgrade or downgrade steps. 2 tracked.
Also searched as: kerberos5.
kerberos 5 has 2 tracked vulnerabilities, 0 critical. A fixed release or vendor patch exists for 2. Most recent: 2026-04-28. Highest priority: CVE-2026-40356 (score 43/100).
- CVE-2026-40356 MEDIUM 5.9 UPGRADE In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if
- CVE-2026-40355 MEDIUM 5.9 UPGRADE In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_ac
FAQ
How do I fix kerberos 5 vulnerabilities?
Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.
Is kerberos 5 being exploited right now?
None of the tracked kerberos 5 CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.
Which kerberos 5 CVE should I patch first?
CVE-2026-40356 currently ranks highest (43/100): In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if .