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CVE-2026-107708VulnerabilityPublished Updated

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

0
Authoritative record:CVE-2026-107708· Medium 6.9

Not known to be exploited · CVSS 6.9 Medium.

Data as of 29 Oct 2026, 00:43 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 26.10krb5pkg:deb/ubuntu/krb5?arch=source&distro=stonkingOther threatsAffected
  • =1.22.1-2ubuntu4
  • =1.22.1-3ubuntu2
Fixed in–
Ubuntu 26.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=resoluteOther threatsAffected
  • 1.21.3-5ubuntu2 – 1.22.1-2ubuntu4.1
6 affected builds
Fixed in–
Ubuntu 24.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=nobleOther threatsAffected
  • 1.20.1-3ubuntu1 – 1.20.1-6ubuntu2.10
13 affected builds
Fixed in–
Ubuntu 22.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=jammyOther threatsAffected
  • 1.18.3-6 – 1.19.2-2ubuntu0.10
14 affected builds
Fixed in–
Ubuntu 20.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=focalOther threatsAffected
  • 1.17-6 – 1.17-6ubuntu4.11
12 affected builds
Fixed in–
Ubuntu Pro 18.04 LTSkrb5pkg:deb/ubuntu/krb5?arch=source&distro=esm-infra/bionicOther threatsAffected
  • 1.15.1-2 – 1.16-2ubuntu0.4+esm5
12 affected builds
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.

References

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