{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68160", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.371Z", "datePublished": "2026-08-10T11:59:26.741Z", "dateUpdated": "2026-08-19T16:30:32.455Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:30:32.455Z" }, "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "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->hdr.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’s 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->front 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->snaps, realm->prior_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—effects an attacker can trigger repeatedly at will." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ceph/caps.c" ], "versions": [ { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "f913192fc782288e060dafc329b2346934be34cc", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "0c011137194036424e974677e0f1592e22a33d8c", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "cc93f68a31c9b831abf2db8647b5f5b10329d793", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "9081c71796724ffe96cba253f68fbe42363c5295", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "03b417afce19ee6b6e61f1bbbbebac924c9f36d1", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "a4228b93706fb74a484e6ffb271c1cc2af3a2ddb", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "71893c342a26bcff92eaab0b2b75d64aed19308a", "status": "affected", "versionType": "git" }, { "version": "a8599bd821d084d04a3290fffae1071624ec00ea", "lessThan": "4dbc71bcaf9a30abf3920a4e2cc4ed33bba78c02", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ceph/caps.c" ], "versions": [ { "version": "2.6.34", "status": "affected" }, { "version": "0", "lessThan": "2.6.34", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.34", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }