CVE-2026-107708

MEDIUM 4.9

MIT krb5 through 1.22.2 KDC NULL Pointer Dereference via S4U2Proxy PAC

CVSS Score

4.9

EPSS Score

0.0%

EPSS Percentile

0th

MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.

CWE	CWE-476
Vendor	mit
Product	krb5
Published	Oct 8, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

MIT / krb5

0 ≤ 1.22.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/krb5/krb5/pull/1510 github.com: https://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7 github.com: https://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86d github.com: https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676 github.com: https://github.com/krb5/krb5 vulncheck.com: https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pac

Credits

Tristan Madani