CVE-2026-40355

EUVD-2026-25981
In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parse_nego_message.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
5.9 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 28%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mitkerberos_5
1.18 ≤
𝑥
< 1.22.3
CNA
Red Hat logo
Red Hat Enterprise Linux Releases
Red Hat Product
Release
krb5-devel
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-libs
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-pkinit
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-server
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-server-ldap
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-workstation
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
krb5-xrealmauthz
RHEL 9
0:1.21.1-10.el9_8
fixed
libkadm5
RHEL 8
0:1.18.2-34.el8_10
fixed
RHEL 9
0:1.21.1-10.el9_8
fixed
Amazon Linux logo
Amazon Linux Releases
Amazon Package
Release
krb5-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-debugsource
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-devel
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-libs
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-libs-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-pkinit
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-pkinit-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-server
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-server-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-server-ldap
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-server-ldap-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-workstation
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
krb5-workstation-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
libkadm5
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
libkadm5-debuginfo
Amazon Linux 2023
0:1.21.3-7.amzn2023.0.1
fixed
Azure Linux logo
Azure Linux Releases
Azure Package
Release
krb5
Azure Linux 3.0
0:1.21.3-4.azl3
fixed
Common Weakness Enumeration
References
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f
https://web.mit.edu/kerberos/advisories/
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html