MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that
Affects krb5Source GCVE Database
Not known to be exploited · CVSS 6.9 Medium.
Data as of 29 Oct 2026, 00:43 UTC
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 8 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10krb5pkg:deb/ubuntu/krb5?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is applied, restrict trust relationships with cross-realm KDCs and monitor for abnormal KDC crashes to mitigate potential denial of service.
Description
MIT krb5 versions through 1.22.2 have a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() function. This flaw causes the function to return success while leaving the client principal NULL when processing malformed names. A malicious or compromised cross-realm trusted KDC can exploit this by sending an S4U2Proxy request with a PAC containing a malformed client name, causing the krb5kdc service to crash and resulting in a denial of authentication service.