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Vulnerability record · CVE-2026-40356 · published 28 April 2026

CVE-2026-40356: Mit kerberos 5 vulnerability

Mit · Kerberos 5

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.

7.5 CVSS 3.1 High EPSS 0.78% · top 45.7% CWE-191 · CWE-191
7.5CVSS 3.1 base score
0.78%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
8 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html ExploitThird Party AdvisoryPatch
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f Patch
https://web.mit.edu/kerberos/advisories/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2011-0285Mit kerberos 5 improper input validation vulnerabilityThe process_chpw_request function in schpw.c in the password-changing functionality in kadmind in MIT Kerberos 5 (aka krb5) 1.7 through 1.9 frees an …EPSS 21%10.0CVE-2009-4212Mit kerberos vulnerabilityMultiple integer underflows in the (1) AES and (2) RC4 decryption functionality in the crypto library in MIT Kerberos 5 (aka krb5) 1.3 through 1.6.3,…EPSS 7.6%10.0CVE-2009-0846Mit kerberos 5 vulnerabilityThe asn1_decode_generaltime function in lib/krb5/asn.1/asn1_decode.c in the ASN.1 GeneralizedTime decoder in MIT Kerberos 5 (aka krb5) before 1.6.4 a…EPSS 8.9%10.0CVE-2008-0947Mit kerberos 5 memory buffer overflow vulnerabilityBuffer overflow in the RPC library used by libgssrpc and kadmind in MIT Kerberos 5 (krb5) 1.4 through 1.6.3 allows remote attackers to execute arbitr…EPSS 8.8%10.0CVE-2007-5902Mit kerberos 5 vulnerabilityInteger overflow in the svcauth_gss_get_principal function in lib/rpc/svc_auth_gss.c in MIT Kerberos 5 (krb5) allows remote attackers to have an unkn…EPSS 5.9%10.0CVE-2007-4743Mit kerberos 5 memory buffer overflow vulnerabilityThe original patch for CVE-2007-3999 in svc_auth_gss.c in the RPCSEC_GSS RPC library in MIT Kerberos 5 (krb5) 1.4 through 1.6.2, as used by the Kerbe…EPSS 4.6%10.0CVE-2007-3999Mit kerberos 5 memory buffer overflow vulnerabilityStack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) in MIT Kerber…EPSS 11%10.0CVE-2007-2442Mit kerberos 5 vulnerabilityThe gssrpc__svcauth_gssapi function in the RPC library in MIT Kerberos 5 (krb5) 1.6.1 and earlier might allow remote attackers to execute arbitrary c…EPSS 11%

Source: NIST National Vulnerability Database (record CVE-2026-40356), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.