Medium 5.9Published Apr 27, 2026

CVE-2026-40356In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registe…

Updated under an hour ago (Oct 26, 2026, 4:20 PM ET)

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Every CVE for MIT Kerberos 5

Exploited in the last 30 days

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read 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, possibly causing the process to terminate in parse_message.

CVSS: 5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-191
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: mitre
NVD analysis: Analyzed
Record last updated: Apr 28, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

MIT Kerberos 5 mit:kerberos_5 (from the name)	from 1.18 before 1.22.3	CNA record
mit kerberos_5 mit:kerberos_5	from 1.18.0 through 1.22.2	NVD

References

References

https://web.mit.edu/kerberos/advisories/	vendor-advisory
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html	exploit, third-party-advisory, patch
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.