{"id":"CVE-2026-68160","title":"ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()","summary":"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 …","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < f913192fc782288e060dafc329b2346934be34cc","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 0c011137194036424e974677e0f1592e22a33d8c","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < cc93f68a31c9b831abf2db8647b5f5b10329d793","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 9081c71796724ffe96cba253f68fbe42363c5295","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 03b417afce19ee6b6e61f1bbbbebac924c9f36d1","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < a4228b93706fb74a484e6ffb271c1cc2af3a2ddb","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 71893c342a26bcff92eaab0b2b75d64aed19308a","Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 4dbc71bcaf9a30abf3920a4e2cc4ed33bba78c02","Linux 2.6.34"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T15:45:20.340785Z"},"published":"2026-08-10","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:53:01.677Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68160","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"}],"tags":["cve.org"],"epss":0.00772,"epssPercentile":0.54802,"ingestedAt":"2026-10-16T17:24:46.846Z","slug":"CVE-2026-68160","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < f913192fc782288e060dafc329b2346934be34cc`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 0c011137194036424e974677e0f1592e22a33d8c`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < cc93f68a31c9b831abf2db8647b5f5b10329d793`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 9081c71796724ffe96cba253f68fbe42363c5295`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 03b417afce19ee6b6e61f1bbbbebac924c9f36d1`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < a4228b93706fb74a484e6ffb271c1cc2af3a2ddb`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 71893c342a26bcff92eaab0b2b75d64aed19308a`\n- `Linux >= a8599bd821d084d04a3290fffae1071624ec00ea < 4dbc71bcaf9a30abf3920a4e2cc4ed33bba78c02`\n- `Linux 2.6.34`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}