CVE-2026-40356

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Source
https://cve.org/CVERecord?id=CVE-2026-40356
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-40356.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-40356
Downstream
Related
Published
2026-04-28T00:00:00Z
Modified
2026-07-14T17:48:17.984336Z
Severity
  • 5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-191"
    ],
    "cna_assigner": "mitre",
    "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"
        }
    ]
}
References

Affected packages

Git / github.com/krb5/krb5

Affected ranges

Type
GIT
Repo
https://github.com/krb5/krb5
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
2e75f0d9362fb979f5fc92829431a590a130929f
Database specific 
{
    "extracted_events": [
        {
            "introduced": "1.18.0"
        },
        {
            "last_affected": "1.22.2"
        }
    ],
    "cpe": "cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*",
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ]
}

Database specific

vanir_signatures 
[
    {
        "target": {
            "file": "src/lib/gssapi/spnego/negoex_util.c",
            "function": "parse_nego_message"
        },
        "id": "CVE-2026-40356-0d8c4b90",
        "signature_type": "Function",
        "deprecated": false,
        "source": "https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f",
        "signature_version": "v1",
        "digest": {
            "function_hash": "142762992336514430865573446923858023953",
            "length": 1059.0
        }
    },
    {
        "target": {
            "file": "src/lib/gssapi/spnego/negoex_util.c"
        },
        "id": "CVE-2026-40356-575ea1f8",
        "signature_type": "Line",
        "deprecated": false,
        "source": "https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f",
        "signature_version": "v1",
        "digest": {
            "line_hashes": [
                "40952602198558450187255405215139956686",
                "188683493495594530274596671268481475985",
                "166540009649839522164965351439044043758",
                "38887152117437256870742115587696304902",
                "211427320194663522795255588816265163872",
                "157791089749722385199311103137710402737",
                "175049674007297452272386585316915970498",
                "125706769889133001570824185629183380644"
            ],
            "threshold": 0.9
        }
    },
    {
        "target": {
            "file": "src/lib/gssapi/spnego/negoex_util.c",
            "function": "parse_message"
        },
        "id": "CVE-2026-40356-e36857fc",
        "signature_type": "Function",
        "deprecated": false,
        "source": "https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f",
        "signature_version": "v1",
        "digest": {
            "function_hash": "250685795234022013172144621242627026091",
            "length": 1843.0
        }
    }
]
source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-40356.json"
vanir_signatures_modified 
"2026-07-14T17:48:17Z"