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CVE-2026-68160

Estado: RecibidaCrítica (9.8)—

In the Linux kernel, the following vulnerability has been resolved:

ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()

ceph_handle_caps() reads snap_trace_len from the wire-format ceph_mds_caps header and uses it unconditionally to build a fake end pointer (snaptrace + snaptrace_len) that is later handed to ceph_update_snap_trace() in the CEPH_CAP_OP_IMPORT case:

ceph_update_snap_trace() then decodes a struct ceph_mds_snap_realm from snaptrace using ceph_decode_need(&p, e, sizeof(*ri), bad) with the attacker-supplied fake end e == snaptrace + snaptrace_len.

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With snaptrace_len == 0xFFFFFFFF the bound check is trivially satisfied, ri = p reads sizeof(struct ceph_mds_snap_realm) past the legitimate msg->front buffer, and ri->num_snaps / ri->num_prior_parent_snaps then drive further out-of-bounds reads of the encoded snap arrays.

The eleven msg_version >= 2 .. msg_version >= 12 decoder blocks above the op switch each catch this OOB through their ceph_decode_*_safe() / ceph_decode_need() helpers, but they sit behind a hdr.version-gated if, so a malicious or compromised MDS that sets msg->hdr.version = 1 reaches the IMPORT path with no version-gated decoder having validated snap_trace_len. The shape has been present since ceph_handle_caps() was introduced.

Validate snap_trace_len against the message front buffer before consuming it, using the canonical ceph_decode_need() / ceph_has_room() helper. The helper bounds the length with subtraction (n <= end - p, guarded by end >= p) rather than pointer addition, so it is wrap-safe for the attacker-controlled u32 length on 32-bit builds where p + snap_trace_len could overflow the address space. This matches the rest of the ceph decode path (e.g. the pool_ns_len check a few lines below), and the existing goto bad cleanup already covers this exit path.

Detalles técnicos trazas, registros y código del informe original
    snaptrace     = h + 1;
    snaptrace_len = le32_to_cpu(h->snap_trace_len);
    p             = snaptrace + snaptrace_len;
    ...
    case CEPH_CAP_OP_IMPORT:
        if (snaptrace_len) {
            ...
            if (ceph_update_snap_trace(mdsc, snaptrace,
                                       snaptrace + snaptrace_len,
                                       false, &realm)) { ... }

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad de lectura fuera de límites en kernel Linux explotable remotamente sin autenticación (AV:N/PR:N/UI:N) por MDS malicioso. Lee datos de memoria arbitrarios vía snaptrace_len manipulado (T1005) y puede causar denegación de servicio (T1499.004).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-68160",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "a8599bd821d084d04a3290fffae1071624ec00ea",
              "lessThan": "f913192fc782288e060dafc329b2346934be34cc",
              "versionType": "git"
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            {
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              "versionType": "git"
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            {
              "status": "affected",
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              "lessThan": "cc93f68a31c9b831abf2db8647b5f5b10329d793",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "9081c71796724ffe96cba253f68fbe42363c5295",
              "versionType": "git"
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            {
              "status": "affected",
              "version": "a8599bd821d084d04a3290fffae1071624ec00ea",
              "lessThan": "03b417afce19ee6b6e61f1bbbbebac924c9f36d1",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a8599bd821d084d04a3290fffae1071624ec00ea",
              "lessThan": "a4228b93706fb74a484e6ffb271c1cc2af3a2ddb",
              "versionType": "git"
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            {
              "status": "affected",
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          ],
          "programFiles": [
            "fs/ceph/caps.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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              "status": "affected",
              "version": "2.6.34"
            },
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              "version": "0",
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              "version": "5.10.265",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
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              "version": "6.18.42",
              "versionType": "semver",
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            },
            {
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ceph/caps.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-10T13:20:02.300",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/03b417afce19ee6b6e61f1bbbbebac924c9f36d1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0c011137194036424e974677e0f1592e22a33d8c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4dbc71bcaf9a30abf3920a4e2cc4ed33bba78c02",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/9081c71796724ffe96cba253f68fbe42363c5295",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a4228b93706fb74a484e6ffb271c1cc2af3a2ddb",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f913192fc782288e060dafc329b2346934be34cc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()\n\nceph_handle_caps() reads snap_trace_len from the wire-format\nceph_mds_caps header and uses it unconditionally to build a fake\nend pointer (snaptrace + snaptrace_len) that is later handed to\nceph_update_snap_trace() in the CEPH_CAP_OP_IMPORT case:\n\n    snaptrace     = h + 1;\n    snaptrace_len = le32_to_cpu(h->snap_trace_len);\n    p             = snaptrace + snaptrace_len;\n    ...\n    case CEPH_CAP_OP_IMPORT:\n        if (snaptrace_len) {\n            ...\n            if (ceph_update_snap_trace(mdsc, snaptrace,\n                                       snaptrace + snaptrace_len,\n                                       false, &realm)) { ... }\n\nceph_update_snap_trace() then decodes a struct ceph_mds_snap_realm\nfrom snaptrace using ceph_decode_need(&p, e, sizeof(*ri), bad)\nwith the attacker-supplied fake end e == snaptrace + snaptrace_len.\nWith snaptrace_len == 0xFFFFFFFF the bound check is trivially\nsatisfied, ri = p reads sizeof(struct ceph_mds_snap_realm) past\nthe legitimate msg->front buffer, and ri->num_snaps /\nri->num_prior_parent_snaps then drive further out-of-bounds\nreads of the encoded snap arrays.\n\nThe eleven msg_version >= 2 .. msg_version >= 12 decoder blocks\nabove the op switch each catch this OOB through their\nceph_decode_*_safe() / ceph_decode_need() helpers, but they sit\nbehind a hdr.version-gated if, so a malicious or compromised\nMDS that sets msg->hdr.version = 1 reaches the IMPORT path with\nno version-gated decoder having validated snap_trace_len. The\nshape has been present since ceph_handle_caps() was introduced.\n\nValidate snap_trace_len against the message front buffer before\nconsuming it, using the canonical ceph_decode_need() / ceph_has_room()\nhelper.  The helper bounds the length with subtraction (n <= end - p,\nguarded by end >= p) rather than pointer addition, so it is wrap-safe\nfor the attacker-controlled u32 length on 32-bit builds where\np + snap_trace_len could overflow the address space.  This matches the\nrest of the ceph decode path (e.g. the pool_ns_len check a few lines\nbelow), and the existing goto bad cleanup already covers this exit\npath."
    }
  ],
  "lastModified": "2026-08-19T17:20:33.317",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}