{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68082", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.367Z", "datePublished": "2026-08-08T09:17:45.394Z", "dateUpdated": "2026-08-23T12:45:46.891Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-23T12:45:46.891Z" }, "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 ]" } ], "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 - The flaw is reached when libceph decodes a crafted MOSDOpReply for the lock.get_info class method received over the Ceph messenger TCP session from a compromised or malicious OSD; no local syscall or ioctl is required on the victim.\nAC:L - A malicious OSD can deterministically send struct_len=0 or craft num_lockers so the decode pointer reaches end, triggering both bare decodes on every attempt without races, special memory layout, or rare kernel configuration.\nPR:N - The attacker acts as the remote Ceph OSD peer and needs no account or privileges on the victim Linux host; any kernel RBD client connected to a multi-tenant or attacker-controlled cluster is exposed during automatic exclusive-lock operations.\nUI:N - Once an RBD image is mapped, ceph_cls_lock_info() is invoked automatically during exclusive-lock acquisition and object-map lock recovery; no further victim user or administrator action is required at exploit time.\nS:U - The slab out-of-bounds reads and any resulting kernel memory corruption occur entirely within the victim host kernel running the Ceph client, without crossing VM, container, or IOMMU security boundaries.\nC:H - Bare ceph_decode_32/8 past the validated reply boundary perform slab out-of-bounds reads of adjacent kernel memory; the leaked u32 can drive kzalloc_objs() sizing and the OOB u8 directly controls the lock-type field consumed by RBD lock logic.\nI:H - Attacker-influenced out-of-bounds values feed heap allocation sizing and lock-type discrimination in kernel lock-handling paths, providing memory-corruption primitives in a privileged parser that can be leveraged beyond simple information disclosure.\nA:H - Slab out-of-bounds reads can trigger KASAN faults or kernel oops on instrumented builds, and attacker-controlled locker counts can force very large kzalloc attempts causing severe memory pressure, OOM conditions, and loss of availability on RBD client hosts." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ceph/cls_lock_client.c" ], "versions": [ { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "c8ade01170a27d8ede0d761c255268af81e417f8", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "001835c599899ef1bd3506a815110a6374451554", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "7c422364acd93d7da1dfc27d6b54635a269653a1", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "02430f6f729b297e803d0605871f0a670b4eafd6", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "57ba829804fe6d34bbac3b826c4b15c1caa54862", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "89df5d71f83f8e2781286798fd8ae5e42cf5f1a7", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "a54be593d0b749161b08a1e56189b2cb9114267a", "status": "affected", "versionType": "git" }, { "version": "d4ed4a530562881cc5225050e42d96034f405aae", "lessThan": "a109a556115271ca7896dcda7b4b7e45e156c227", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ceph/cls_lock_client.c" ], "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.266", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.217", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.184", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.153", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.105", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.46", "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": "4.9", "versionEndExcluding": "5.10.266" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.15.217" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.1.184" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.6.153" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.105" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.46" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c8ade01170a27d8ede0d761c255268af81e417f8" }, { "url": "https://git.kernel.org/stable/c/001835c599899ef1bd3506a815110a6374451554" }, { "url": "https://git.kernel.org/stable/c/7c422364acd93d7da1dfc27d6b54635a269653a1" }, { "url": "https://git.kernel.org/stable/c/02430f6f729b297e803d0605871f0a670b4eafd6" }, { "url": "https://git.kernel.org/stable/c/57ba829804fe6d34bbac3b826c4b15c1caa54862" }, { "url": "https://git.kernel.org/stable/c/89df5d71f83f8e2781286798fd8ae5e42cf5f1a7" }, { "url": "https://git.kernel.org/stable/c/a54be593d0b749161b08a1e56189b2cb9114267a" }, { "url": "https://git.kernel.org/stable/c/a109a556115271ca7896dcda7b4b7e45e156c227" } ], "title": "libceph: fix two unsafe bare decodes in decode_lockers()", "x_generator": { "engine": "bippy-1.2.0" } } } }