Vulnerability Details CVE-2026-40355
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 39.9%
CVSS Severity
CVSS v3 Score 5.9
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
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
Products affected by CVE-2026-40355
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cpe:2.3:a:mit:kerberos_5:1.18.0
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cpe:2.3:a:mit:kerberos_5:1.18.1
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cpe:2.3:a:mit:kerberos_5:1.18.2
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cpe:2.3:a:mit:kerberos_5:1.18.3
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cpe:2.3:a:mit:kerberos_5:1.18.4
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cpe:2.3:a:mit:kerberos_5:1.19.0
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cpe:2.3:a:mit:kerberos_5:1.19.1
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cpe:2.3:a:mit:kerberos_5:1.19.2
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cpe:2.3:a:mit:kerberos_5:1.19.3
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cpe:2.3:a:mit:kerberos_5:1.19.4
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cpe:2.3:a:mit:kerberos_5:1.20
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cpe:2.3:a:mit:kerberos_5:1.20.1
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cpe:2.3:a:mit:kerberos_5:1.20.2
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cpe:2.3:a:mit:kerberos_5:1.21
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cpe:2.3:a:mit:kerberos_5:1.21.1
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cpe:2.3:a:mit:kerberos_5:1.21.2