CVE-2026-107708
published 2026-10-08CVE-2026-107708: 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…
PriorityP425medium4.9CVSS 3.1
AVNACLPRHUINSUCNINAH
EPSS
0.52%
43.4th percentile
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.
Affected
17 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| migration-toolkit-virtualization | mtv-virt-v2v-rhel10 | — | — |
| mit | krb5 | <= 1.22.2 | — |
| mit | krb5 | — | — |
| openshift | ose-rhel-coreos-8 | — | — |
| openshift | ose-rhel-coreos-9 | — | — |
| openshift4 | driver-toolkit-rhel9 | — | — |
| openshift4 | ose-ironic-machine-os-downloader-rhel9 | — | — |
| rhcertification | redhat-certification-baremetal | — | — |
| rhcertification | redhat-certification-system-ai-10 | — | — |
| rhcertification | redhat-certification-system-ai-9 | — | — |
| rhel10-eus | rhel-10.0-bootc | — | — |
| rhel10-eus | rhel-10.2-bootc | — | — |
| rhel10 | rhel-bootc | — | — |
| rhel9-eus | rhel-9.6-bootc | — | — |
| rhel9-eus | rhel-9.8-bootc | — | — |
| rhel9 | rhel-bootc | — | — |
| rhoso | openstack-nova-compute-rhel9 | — | — |
CVSS provenance
nvdv3.14.9MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
nvdv4.06.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat4.9MEDIUM
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Red Hat
krb5: krb5: Denial of Service via malformed PAC in S4U2Proxy requests
vendor_redhat·2026-10-08·CVSS 4.9
CVE-2026-107708 [MEDIUM] CWE-476 krb5: krb5: Denial of Service via malformed PAC in S4U2Proxy requests
krb5: krb5: Denial of Service via malformed PAC in S4U2Proxy requests
A flaw was found in krb5. This vulnerability allows a compromised or malicious cross-realm trusted Key Distribution Center (KDC) to cause a Denial of Service (DoS). By sending an S4U2Proxy delegation request containing a malformed client name within a Privilege Attribute Certificate (PAC), an attacker can trigger a NULL pointer dereference that crashes the KDC daemon, interrupting authentication services.
Package: migration-toolkit-virtualization/mtv-virt-v2v-rhel10 (Migration Toolkit for Virtualization) - Fix deferred
Package: rhcertification/redhat-certification-baremetal (Red Hat Certification Program for Red Hat Enterprise Linux 9) - Fix deferred
Package: rhcertification/redhat-certification-system-ai-10 (Red Hat
VulDB
MIT krb5 up to 1.22.2 KDC get_pac_princ_with_realm null pointer dereference (Nessus ID 364715 / WID-SEC-2026-3836)
vuldb·2026-10-13·CVSS 4.9
CVE-2026-107708 [MEDIUM] MIT krb5 up to 1.22.2 KDC get_pac_princ_with_realm null pointer dereference (Nessus ID 364715 / WID-SEC-2026-3836)
A vulnerability marked as problematic has been reported in MIT krb5 up to 1.22.2. The impacted element is the function get_pac_princ_with_realm of the component KDC. Performing a manipulation results in null pointer dereference.
This vulnerability is reported as CVE-2026-107708. The attack is possible to be carried out remotely. No exploit exists.
GHSA
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.
ghsa_unreviewed·2026-10-08
CVE-2026-107708 [MEDIUM] CWE-476 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.
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.
No detection rules found.
No public exploits indexed.
https://github.com/krb5/krb5https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676https://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86dhttps://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7https://github.com/krb5/krb5/pull/1510https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pac
2026-10-08
Published