CVE-2026-68433 (GCVE-0-2026-68433)

Vulnerability from cvelistv5 – Published: 2026-08-12 00:07 – Updated: 2026-08-19 16:35
VLAI
Title
libceph: bound get_version reply decode to front len
Summary
In the Linux kernel, the following vulnerability has been resolved: libceph: bound get_version reply decode to front len handle_get_version_reply() uses msg->front_alloc_len as the decode boundary for MON_GET_VERSION_REPLY. That is the size of the reused reply buffer, not the number of bytes actually received. A truncated reply can therefore pass ceph_decode_need() and decode the second u64 from stale tail bytes left in the buffer by an earlier message, causing an uninitialized memory read. Use msg->front.iov_len as the receive-side decode boundary, matching other libceph reply handlers and limiting decoding to the bytes that were actually read from the wire.
Severity
8.6 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < 1307028f082756bf453e1889aee9983d30643a4b (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < f6cbf6878f3a1503c872ba8f1e69a58ee68d8b2e (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < 72a35070fcefa229b1b031aa7482ad3788e18f07 (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < 340e0386aa39da181015bee38f309018c335ce16 (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < d60de8253c85a02d0e6194b0735e7a562981a04c (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < 4e7ebfaa0d14cf50e44041bfde38070d6dbc019f (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < 0d934c934ec746d53fc7e4f53239792647bbae63 (git)
Affected: 513a8243d67f8e8d27f2883bd2f18bc87c7ca376 , < d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0 (git)
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Linux Linux Affected: 3.16
Unaffected: 0 , < 3.16 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.148 , ≤ 6.6.* (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "net/ceph/mon_client.c"
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              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
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      "cpeApplicability": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.265",
                  "versionStartIncluding": "3.16",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "5.15.216",
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                  "vulnerable": true
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                  "vulnerable": true
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                  "versionStartIncluding": "3.16",
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                  "vulnerable": true
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                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "3.16",
                  "vulnerable": true
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                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "3.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: bound get_version reply decode to front len\n\nhandle_get_version_reply() uses msg-\u003efront_alloc_len as the decode\nboundary for MON_GET_VERSION_REPLY.  That is the size of the reused\nreply buffer, not the number of bytes actually received.\n\nA truncated reply can therefore pass ceph_decode_need() and decode the\nsecond u64 from stale tail bytes left in the buffer by an earlier\nmessage, causing an uninitialized memory read.\n\nUse msg-\u003efront.iov_len as the receive-side decode boundary, matching\nother libceph reply handlers and limiting decoding to the bytes that\nwere actually read from the wire."
        }
      ],
      "metrics": [
        {
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            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The malformed MON_GET_VERSION_REPLY arrives over the ceph messenger TCP connection to a monitor; a malicious/compromised ceph-mon or an on-path attacker on the msgr1/crc-mode session triggers the bug purely with received network data.\nAC:L - The attacker fully controls the reply\u0027s hdr.front_len and tid, so truncating the reply to 8 bytes reliably makes the handler decode past the received data every time; no race or memory-layout condition outside attacker control is involved.\nPR:N - The vulnerable decode runs on any reply the client accepts for an outstanding generic request; the attacker acts as the remote server/peer and needs no credentials or account on the victim kernel client.\nUI:N - An already-mounted CephFS/RBD client issues mon_get_version requests automatically (osdmap checks, pool-dne checks, remount/latest-map waits), so no local user action is needed once the client is connected.\nS:U - The uninitialized read and the resulting bogus epoch stay within the kernel\u0027s own libceph client state; no security authority other than the affected kernel is impacted.\nC:L - Eight bytes of uninitialized kvmalloc\u0027d heap (or stale bytes of a prior reply) are consumed as req-\u003eu.newest; the read stays inside the 32-byte allocation and is not copied to userspace, so it is a small bounded uninitialized-memory disclosure that only leaks indirectly through client behaviour.\nI:L - The attacker causes kernel state (req-\u003eu.newest, r_map_dne_bound, linger map_dne_bound) to be populated from uninitialized memory rather than the wire, corrupting osdmap-epoch bookkeeping and leading to wrong pool-does-not-exist decisions, but gives no arbitrary write.\nA:H - A zero stale value trips WARN_ON(greq-\u003eresult || !greq-\u003eu.newest) in map_check_cb()/linger_map_check_cb() (panic with panic_on_warn), while a huge garbage epoch makes ceph_monc_wait_osdmap() block until mount_timeout or indefinitely and makes check_pool_dne() abort in-flight requests with -ENOENT; all repeatable at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:35:33.508Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1307028f082756bf453e1889aee9983d30643a4b"
        },
        {
          "url": "https://git.kernel.org/stable/c/f6cbf6878f3a1503c872ba8f1e69a58ee68d8b2e"
        },
        {
          "url": "https://git.kernel.org/stable/c/72a35070fcefa229b1b031aa7482ad3788e18f07"
        },
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          "url": "https://git.kernel.org/stable/c/340e0386aa39da181015bee38f309018c335ce16"
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          "url": "https://git.kernel.org/stable/c/d60de8253c85a02d0e6194b0735e7a562981a04c"
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          "url": "https://git.kernel.org/stable/c/d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0"
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      "title": "libceph: bound get_version reply decode to front len",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68433",
    "datePublished": "2026-08-12T00:07:20.455Z",
    "dateReserved": "2026-07-30T09:28:09.393Z",
    "dateUpdated": "2026-08-19T16:35:33.508Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "cve": "CVE-2026-68433",
      "date": "2026-08-24",
      "epss": "0.00291",
      "percentile": "0.21028"
    },
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That is the size of the reused\\nreply buffer, not the number of bytes actually received.\\n\\nA truncated reply can therefore pass ceph_decode_need() and decode the\\nsecond u64 from stale tail bytes left in the buffer by an earlier\\nmessage, causing an uninitialized memory read.\\n\\nUse msg-\u003efront.iov_len as the receive-side decode boundary, matching\\nother libceph reply handlers and limiting decoding to the bytes that\\nwere actually read from the wire.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/ceph/mon_client.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"1307028f082756bf453e1889aee9983d30643a4b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"f6cbf6878f3a1503c872ba8f1e69a58ee68d8b2e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"72a35070fcefa229b1b031aa7482ad3788e18f07\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"340e0386aa39da181015bee38f309018c335ce16\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"d60de8253c85a02d0e6194b0735e7a562981a04c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"4e7ebfaa0d14cf50e44041bfde38070d6dbc019f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"0d934c934ec746d53fc7e4f53239792647bbae63\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"513a8243d67f8e8d27f2883bd2f18bc87c7ca376\",\"lessThan\":\"d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/ceph/mon_client.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"3.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.265\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.216\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H\",\"baseScore\":8.6,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":4.7}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0d934c934ec746d53fc7e4f53239792647bbae63\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1307028f082756bf453e1889aee9983d30643a4b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/340e0386aa39da181015bee38f309018c335ce16\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4e7ebfaa0d14cf50e44041bfde38070d6dbc019f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/72a35070fcefa229b1b031aa7482ad3788e18f07\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d60de8253c85a02d0e6194b0735e7a562981a04c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f6cbf6878f3a1503c872ba8f1e69a58ee68d8b2e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T01:20:16+00:00",
      "cve": "CVE-2026-68433",
      "id": "CVE-2026-68433",
      "initial_release_date": "2026-08-12T00:00:00+00:00",
      "product_status:known_affected": "261",
      "product_status:known_not_affected": "15",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: libceph: bound get_version reply decode to front len",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68433.json",
      "version": "3"
    }
  }
}



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