CVE-2026-64208 (GCVE-0-2026-64208)
Vulnerability from cvelistv5
Published
2026-07-24 15:23
Modified
2026-08-05 12:40
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks Change the krb5 crypto library to provide facilities to precheck the length of the message about to be decrypted or verified. Fix AF_RXRPC to make use of this to validate DATA packets secured with RxGK.
References
Impacted products
Vendor Product Version
Linux Linux Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
Version: 9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "Documentation/crypto/krb5.rst",
            "crypto/krb5/krb5_api.c",
            "include/crypto/krb5.h",
            "include/trace/events/rxrpc.h",
            "net/rxrpc/rxgk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff",
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "versionType": "git"
            },
            {
              "lessThan": "9217017f4bce53dddb8d547837f1f707045d64ad",
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "versionType": "git"
            },
            {
              "lessThan": "2b50aceafe6606ea52ed42aadd1b4d44a188aade",
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "Documentation/crypto/krb5.rst",
            "crypto/krb5/krb5_api.c",
            "include/crypto/krb5.h",
            "include/trace/events/rxrpc.h",
            "net/rxrpc/rxgk.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks\n\nChange the krb5 crypto library to provide facilities to precheck the length\nof the message about to be decrypted or verified.\n\nFix AF_RXRPC to make use of this to validate DATA packets secured with\nRxGK."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Attacker-controlled RxRPC DATA packets reach the vulnerable RxGK verifier over UDP. A malicious contacted server can exercise the client receive path without network proximity.\nAC:L - A single deliberately short packet triggers the faulty length handling without a race or uncontrollable condition. Visible RxRPC header fields allow the peer to target an active call reliably.\nPR:N - The length handling occurs before MIC verification or decryption authenticates the packet. A malicious RxRPC server therefore needs no valid Kerberos key or credentials.\nUI:N - No human action is required once an application or mounted AFS/YFS client communicates over the RxGK connection. Packet processing and call termination occur automatically.\nS:U - The vulnerable RxRPC processing and resulting impact remain within the host kernel\u0027s security authority. No VM, sandbox, or IOMMU boundary is crossed.\nC:N - The underlying Kerberos implementations reject blobs shorter than their cryptographic overhead before accessing packet data. No out-of-bounds read or information disclosure is supported by the affected path.\nI:N - The malformed length does not produce an out-of-bounds write or attacker-controlled modification. Existing post-decryption checks prevent reading or applying a truncated inner header.\nA:H - A short unauthenticated packet aborts the active RxRPC call, and repeated injections can continuously deny RxGK-protected AFS/YFS operations. This can make a critical network filesystem or dependent service unavailable."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:40:02.002Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/585f9f6aef5c4542ac9d6ec45cd7dbc7df9af3ff"
        },
        {
          "url": "https://git.kernel.org/stable/c/9217017f4bce53dddb8d547837f1f707045d64ad"
        },
        {
          "url": "https://git.kernel.org/stable/c/2b50aceafe6606ea52ed42aadd1b4d44a188aade"
        }
      ],
      "title": "crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64208",
    "datePublished": "2026-07-24T15:23:00.113Z",
    "dateReserved": "2026-07-19T15:36:31.769Z",
    "dateUpdated": "2026-08-05T12:40:02.002Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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