CVE-2026-68082
Estado: RecibidaCrítica (9.8)—
In the Linux kernel, the following vulnerability has been resolved:
libceph: fix two unsafe bare decodes in decode_lockers()
decode_lockers() in cls_lock_client.c contains two bare decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads:
ret is set to -EINVAL before ceph_decode_8_safe() so that err_free_lockers returns the correct error code on bounds violation. Without this, err_free_lockers would return a stale ret value (0 from the successful decode_locker() loop), silently swallowing the error.
-EINVAL is correct for both failure paths. The data received from the OSD is structurally malformed. -ENOMEM would misrepresent the failure class to callers and to stable@ backporters triaging error paths.
Leer descripción completaMostrar menos
Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment can trigger this against any kernel client that issues the lock.get_info class method (e.g. during RBD exclusive lock acquisition).
[ idryomov: trim changelog, formatting ]
Detalles técnicos trazas, registros y código del informe original
1. ceph_decode_32(p) at the num_lockers field has no preceding bounds
check. ceph_start_decoding() accepts struct_len=0 as valid -- the
internal ceph_decode_need(p, end, 0, bad) always passes -- so when an
OSD sends struct_len=0, ceph_start_decoding() returns success with
p == end. The immediately following bare ceph_decode_32(p) then reads
4 bytes past the validated buffer boundary. The garbage value is
passed directly to kzalloc_objs() as the locker count.
The sibling function decode_watchers() in osd_client.c already uses
ceph_decode_32_safe() after its own ceph_start_decoding() call.
decode_lockers() was the only site using the bare variant.
2. ceph_decode_8(p) after the decode_locker() loop has no preceding
bounds check. If an OSD crafts num_lockers such that the loop
advances p exactly to end, the subsequent bare ceph_decode_8(p) reads
one byte past the validated buffer boundary. The result is passed
directly into *type, which is used as a lock type discriminator by
callers, giving an OSD-controlled one-byte OOB read with direct
influence over the lock type field.
Fix both by replacing bare operations with their safe variants:
ceph_decode_32(p) -> ceph_decode_32_safe(p, end, *num_lockers,
err_inval)
ceph_decode_8(p) -> ceph_decode_8_safe(p, end, *type,
err_free_lockers)
The goto targets differ intentionally:
err_inval: is a new label returning -EINVAL directly. It is used for
the pre-allocation failure path where *lockers is not yet allocated
and must not be passed to ceph_free_lockers().
err_free_lockers: is the existing label. It is used for the
post-allocation failure path where *lockers is allocated and must
be freed.CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 9.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.40%
- Percentil entre todas las CVEs puntuadas: 32
- Fecha de la puntuación: 5/10/2026
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.
- Explotación
T1190Exploit Public-Facing Applicationinitial access60 %
Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.
🛡️ 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
- https://git.kernel.org/stable/c/001835c599899ef1bd3506a815110a6374451554
- https://git.kernel.org/stable/c/02430f6f729b297e803d0605871f0a670b4eafd6
- https://git.kernel.org/stable/c/57ba829804fe6d34bbac3b826c4b15c1caa54862
- https://git.kernel.org/stable/c/7c422364acd93d7da1dfc27d6b54635a269653a1
- https://git.kernel.org/stable/c/89df5d71f83f8e2781286798fd8ae5e42cf5f1a7
- https://git.kernel.org/stable/c/a109a556115271ca7896dcda7b4b7e45e156c227
- https://git.kernel.org/stable/c/a54be593d0b749161b08a1e56189b2cb9114267a
- https://git.kernel.org/stable/c/c8ade01170a27d8ede0d761c255268af81e417f8
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-68082",
"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": [
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"vendor": "Linux",
"product": "Linux",
"versions": [
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"status": "affected",
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],
"programFiles": [
"net/ceph/cls_lock_client.c"
],
"defaultStatus": "unaffected"
},
{
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"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
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{
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver",
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{
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"version": "6.18.46",
"versionType": "semver",
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{
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{
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"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
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],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-08T10:16:55.377",
"references": [
{
"url": "https://git.kernel.org/stable/c/001835c599899ef1bd3506a815110a6374451554",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"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/a109a556115271ca7896dcda7b4b7e45e156c227",
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c8ade01170a27d8ede0d761c255268af81e417f8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: fix two unsafe bare decodes in decode_lockers()\n\ndecode_lockers() in cls_lock_client.c contains two bare decode operations\nthat allow a malicious or compromised OSD to trigger slab-out-of-bounds\nreads:\n\n1. ceph_decode_32(p) at the num_lockers field has no preceding bounds\n check. ceph_start_decoding() accepts struct_len=0 as valid -- the\n internal ceph_decode_need(p, end, 0, bad) always passes -- so when an\n OSD sends struct_len=0, ceph_start_decoding() returns success with\n p == end. The immediately following bare ceph_decode_32(p) then reads\n 4 bytes past the validated buffer boundary. The garbage value is\n passed directly to kzalloc_objs() as the locker count.\n\n The sibling function decode_watchers() in osd_client.c already uses\n ceph_decode_32_safe() after its own ceph_start_decoding() call.\n decode_lockers() was the only site using the bare variant.\n\n2. ceph_decode_8(p) after the decode_locker() loop has no preceding\n bounds check. If an OSD crafts num_lockers such that the loop\n advances p exactly to end, the subsequent bare ceph_decode_8(p) reads\n one byte past the validated buffer boundary. The result is passed\n directly into *type, which is used as a lock type discriminator by\n callers, giving an OSD-controlled one-byte OOB read with direct\n influence over the lock type field.\n\nFix both by replacing bare operations with their safe variants:\n ceph_decode_32(p) -> ceph_decode_32_safe(p, end, *num_lockers,\n err_inval)\n ceph_decode_8(p) -> ceph_decode_8_safe(p, end, *type,\n err_free_lockers)\n\nThe goto targets differ intentionally:\n err_inval: is a new label returning -EINVAL directly. It is used for\n the pre-allocation failure path where *lockers is not yet allocated\n and must not be passed to ceph_free_lockers().\n\n err_free_lockers: is the existing label. It is used for the\n post-allocation failure path where *lockers is allocated and must\n be freed.\n\nret is set to -EINVAL before ceph_decode_8_safe() so that\nerr_free_lockers returns the correct error code on bounds violation.\nWithout this, err_free_lockers would return a stale ret value (0 from\nthe successful decode_locker() loop), silently swallowing the error.\n\n-EINVAL is correct for both failure paths. The data received from the\nOSD is structurally malformed. -ENOMEM would misrepresent the failure\nclass to callers and to stable@ backporters triaging error paths.\n\nAttacker model: a malicious or compromised OSD in a multi-tenant Ceph\ndeployment can trigger this against any kernel client that issues the\nlock.get_info class method (e.g. during RBD exclusive lock acquisition).\n\n[ idryomov: trim changelog, formatting ]"
}
],
"lastModified": "2026-08-23T13:16:32.583",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}