CVE-2026-43304 (GCVE-0-2026-43304)
Vulnerability from cvelistv5
Published
2026-05-08 13:11
Modified
2026-08-05 12:27
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: libceph: define and enforce CEPH_MAX_KEY_LEN When decoding the key, verify that the key material would fit into a fixed-size buffer in process_auth_done() and generally has a sane length. The new CEPH_MAX_KEY_LEN check replaces the existing check for a key with no key material which is a) not universal since CEPH_CRYPTO_NONE has to be excluded and b) doesn't provide much value since a smaller than needed key is just as invalid as no key -- this has to be handled elsewhere anyway.
References
Impacted products
Vendor Product Version
Linux Linux Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
Version: cd1a677cad994021b19665ed476aea63f5d54f31
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ceph/crypto.c",
            "net/ceph/crypto.h",
            "net/ceph/messenger_v2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "net/ceph/crypto.h",
            "net/ceph/messenger_v2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "5.11"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.15.202",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
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              "version": "6.6.128",
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            },
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              "status": "unaffected",
              "version": "6.12.75",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.202",
                  "versionStartIncluding": "5.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.165",
                  "versionStartIncluding": "5.11",
                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.0",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: define and enforce CEPH_MAX_KEY_LEN\n\nWhen decoding the key, verify that the key material would fit into\na fixed-size buffer in process_auth_done() and generally has a sane\nlength.\n\nThe new CEPH_MAX_KEY_LEN check replaces the existing check for a key\nwith no key material which is a) not universal since CEPH_CRYPTO_NONE\nhas to be excluded and b) doesn\u0027t provide much value since a smaller\nthan needed key is just as invalid as no key -- this has to be handled\nelsewhere anyway."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable path is reached by TCP data received from a Ceph msgr2 peer during monitor/OSD authentication, through sock_recvmsg() to process_auth_done(). A malicious or compromised Ceph endpoint can supply the crafted AUTH_DONE payload over the network.\nAC:L - Once the attacker can act as the responding Ceph peer, the oversized decoded session key is a deterministic protocol field and no race or hard-to-control condition is required. The stack overwrite follows directly from the key length accepted before the fix.\nPR:N - The attacker needs no local privileges on the victim kernel; the code is reached during the network authentication handshake before the connection is fully established. Even though CephX payloads are cryptographic, a malicious configured/compromised peer can trigger the path remotely.\nUI:N - No interactive victim action is required once the vulnerable client connects to the Ceph peer as part of normal operation. The malicious AUTH_DONE response is processed automatically by the kernel client.\nS:U - The impact is compromise or crash of the same kernel/client security authority that contains the vulnerable libceph code. This is not a VM escape, IOMMU bypass, or other cross-scope boundary violation.\nC:H - The bug is attacker-controlled kernel stack memory corruption from copying an unchecked session key into a fixed-size stack buffer. Such memory corruption can reasonably be leveraged for sensitive kernel memory disclosure.\nI:H - The unchecked memcpy can overwrite adjacent kernel stack state with attacker-controlled key bytes. This is an out-of-bounds write with plausible control-flow or data corruption impact.\nA:H - The stack overflow can corrupt kernel execution state and cause an oops or panic. Even without full exploitation, a malicious peer can crash the client kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:09.910Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6405e8c680974bb74e2c98d5249fb52c7b12a6c6"
        },
        {
          "url": "https://git.kernel.org/stable/c/8d745d38c88ecbed95f6b2b39857bf89f35a3244"
        },
        {
          "url": "https://git.kernel.org/stable/c/e1dc45d97975f9db65694d234fbddf1915176e16"
        },
        {
          "url": "https://git.kernel.org/stable/c/1b275bd49e58752efb83767a5d1aed41356c5e64"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1a0f5f1e5e7e98c36a362ec3d1fcfd9932931ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/d82467c07b03a27c3c5469b62bb3b726305a80bb"
        },
        {
          "url": "https://git.kernel.org/stable/c/ac431d597a9bdfc2ba6b314813f29a6ef2b4a3bf"
        }
      ],
      "title": "libceph: define and enforce CEPH_MAX_KEY_LEN",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43304",
    "datePublished": "2026-05-08T13:11:24.264Z",
    "dateReserved": "2026-05-01T14:12:56.000Z",
    "dateUpdated": "2026-08-05T12:27:09.910Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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