CVE-2026-40356

{
  "id": "CVE-2026-40356",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-28T07:16:03.197",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "En MIT Kerberos 5 (también conocido como krb5) antes de la versión 1.22.3, existe un desbordamiento negativo de enteros y una lectura fuera de límites resultante si una aplicación llama a gss_accept_sec_context() en un sistema con un mecanismo NegoEx registrado en /etc/gss/mech. Un atacante remoto no autenticado puede desencadenar esto, posiblemente causando que el proceso termine en parse_message."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "MIT",
          "product": "Kerberos 5",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1.18",
              "lessThan": "1.22.3",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      },
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-28T13:10:05.740836Z",
          "id": "CVE-2026-40356",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-191"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "1.18.0",
              "versionEndIncluding": "1.22.2",
              "matchCriteriaId": "7A5665F4-71F4-4A71-A0A0-1E1F2BECA288"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html",
      "source": "[email protected]",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "Patch"
      ]
    },
    {
      "url": "https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://web.mit.edu/kerberos/advisories/",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}