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 gssacceptseccontext() 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 parsemessage.
{
"cwe_ids": [
"CWE-191"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40356.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"introduced": "1.18"
},
{
"fixed": "1.22.3"
}
],
"source": "AFFECTED_FIELD"
},
{
"extracted_events": [
{
"introduced": "1.18"
},
{
"fixed": "1.22.3"
}
],
"source": "CPE_FIELD"
},
{
"extracted_events": [
{
"fixed": "1.22.3"
}
],
"source": "DESCRIPTION"
}
],
"cna_assigner": "mitre"
}{
"cpe": "cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "1.18.0"
},
{
"last_affected": "1.22.2"
}
],
"source": [
"CPE_RANGE",
"REFERENCES"
]
}