CVE-2026-68160 (GCVE-0-2026-68160)
Vulnerability from cvelistv5
Published
2026-08-10 11:59
Modified
2026-08-19 16:30
Severity ?
VLAI Severity ?
EPSS score ?
Summary
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:
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)) { ... }
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.
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea Version: a8599bd821d084d04a3290fffae1071624ec00ea |
||
{
"containers": {
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{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ceph/caps.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"programFiles": [
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],
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"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "2.6.34"
},
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"vulnerable": true
},
{
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},
{
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{
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{
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{
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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-\u003esnap_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, \u0026realm)) { ... }\n\nceph_update_snap_trace() then decodes a struct ceph_mds_snap_realm\nfrom snaptrace using ceph_decode_need(\u0026p, 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-\u003efront buffer, and ri-\u003enum_snaps /\nri-\u003enum_prior_parent_snaps then drive further out-of-bounds\nreads of the encoded snap arrays.\n\nThe eleven msg_version \u003e= 2 .. msg_version \u003e= 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-\u003ehdr.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 \u003c= end - p,\nguarded by end \u003e= 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."
}
],
"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 - CEPH_MSG_CLIENT_CAPS is received over the kernel Ceph messenger TCP connection from an MDS peer; mds_dispatch() passes it directly to ceph_handle_caps(), so a malicious or compromised MDS (or on-path attacker on an unsigned msgr session) reaches the bug with network data alone.\nAC:L - The attacker fully controls msg-\u003ehdr.version and snap_trace_len in the caps header; setting version=1 bypasses all version-gated decoders and snap_trace_len=0xFFFFFFFF yields a fake end pointer that reliably defeats ceph_decode_need(), with no race or memory-layout dependency.\nPR:N - Exploitation requires only the ability to send crafted caps messages as the remote MDS peer on an established session; the attacker needs no account, mount privilege, or other credentials on the victim host beyond the client already being connected to that cluster.\nUI:N - Once CephFS is mounted and the MDS session is open, CEPH_CAP_OP_IMPORT caps messages are delivered and processed automatically during normal cap migration and MDS failover; no additional local user action is needed at exploit time beyond prior cluster connectivity.\nS:U - The out-of-bounds read and resulting snap-realm corruption affect only the kernel CephFS client\u2019s internal state within the same kernel security authority; there is no VM escape, sandbox breakout, or cross-authority boundary crossing.\nC:H - ceph_update_snap_trace() decodes struct ceph_mds_snap_realm and snap arrays using an attacker-supplied fake end pointer, reading sizeof(*ri) and further attacker-influenced extents past the legitimate msg-\u003efront buffer into adjacent kernel memory without copying to userspace.\nI:H - Out-of-bounds kernel memory is interpreted as snap-realm metadata and copied via dup_array() into newly allocated kernel heap structures (realm-\u003esnaps, realm-\u003eprior_parent_snaps), corrupting authoritative snap state and providing a memory-corruption primitive that could be leveraged for further kernel compromise.\nA:H - Out-of-bounds reads can fault on unmapped pages causing a kernel oops; the ceph_update_snap_trace() error path issues WARN(1), fences I/O via CEPH_MOUNT_FENCE_IO, and can close all MDS sessions\u2014effects an attacker can trigger repeatedly at will."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:30:32.455Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f913192fc782288e060dafc329b2346934be34cc"
},
{
"url": "https://git.kernel.org/stable/c/0c011137194036424e974677e0f1592e22a33d8c"
},
{
"url": "https://git.kernel.org/stable/c/cc93f68a31c9b831abf2db8647b5f5b10329d793"
},
{
"url": "https://git.kernel.org/stable/c/9081c71796724ffe96cba253f68fbe42363c5295"
},
{
"url": "https://git.kernel.org/stable/c/03b417afce19ee6b6e61f1bbbbebac924c9f36d1"
},
{
"url": "https://git.kernel.org/stable/c/a4228b93706fb74a484e6ffb271c1cc2af3a2ddb"
},
{
"url": "https://git.kernel.org/stable/c/71893c342a26bcff92eaab0b2b75d64aed19308a"
},
{
"url": "https://git.kernel.org/stable/c/4dbc71bcaf9a30abf3920a4e2cc4ed33bba78c02"
}
],
"title": "ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68160",
"datePublished": "2026-08-10T11:59:26.741Z",
"dateReserved": "2026-07-30T09:28:09.371Z",
"dateUpdated": "2026-08-19T16:30:32.455Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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