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CVE-2026-40356

Published: Apr 28, 2026Updated: Apr 28, 2026 Sources: CVE List NVDCWE-191
5.9MEDIUM
NVD MITRE
EPSS Score
0.5%
Top 63.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
OpenVAS

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-191

Affected Products

MIT
oss-project·USaka mit krb5, mit kerberos
Kerberos 5On-prem
Operating Systems

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://web.mit.edu/kerberos/advisories/
web.mit.edu
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html
cems.fun
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f
github.com
News mentions
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