{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80557", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.767Z", "datePublished": "2026-08-26T14:37:24.178Z", "dateUpdated": "2026-10-16T19:26:26.946Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T12:40:16.573Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: fix OOB read in decode_watchers() via missing bounds check\n\nceph_start_decoding() validates that struct_len bytes remain in the\nbuffer after the encoding header, but accepts struct_len=0 as valid:\nceph_decode_need(p, end, 0, bad) always passes. When a malicious or\ncompromised OSD sends an obj_list_watch_response_t reply with\nstruct_len=0, ceph_start_decoding() returns success with p == end,\nleaving zero bytes guaranteed for subsequent reads.\n\nThe immediately following ceph_decode_32(p) in decode_watchers() has\nno preceding bounds check. With p == end this is a 4-byte read past\nthe validated buffer boundary. The garbage value is then passed\ndirectly to kzalloc_objs() as the watcher count.\n\nThe sibling function decode_watcher() already uses the safe variants\n(ceph_decode_copy_safe, ceph_decode_64_safe, ceph_decode_skip_32)\nafter its own ceph_start_decoding() call. decode_watchers() is the\nonly site that uses the bare variant, confirming an oversight.\n\nFix by replacing ceph_decode_32(p) with ceph_decode_32_safe(p, end,\n*num_watchers, bad), consistent with the established pattern.\n\nAttacker model: a malicious or compromised OSD in a multi-tenant Ceph\ndeployment (e.g. cloud) can trigger this against any kernel client\nthat calls CEPH_OSD_OP_LIST_WATCHERS, without any further privileges\nbeyond OSD session establishment.\n\n[ idryomov: trim changelog ]" } ], "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 bug is triggered when libceph decodes a crafted MOSDOpReply for CEPH_OSD_OP_LIST_WATCHERS received over the Ceph messenger TCP session from a compromised or malicious OSD; exploitation requires no local syscall, ioctl, or device access on the victim.\nAC:L - A malicious OSD fully controls the reply encoding and can set struct_len=0 with a chosen outdata_len so ceph_start_decoding() leaves p at end and the following ceph_decode_32() deterministically reads attacker-chosen bytes as num_watchers without races or victim-specific memory layout.\nPR:N - The attacker acts as the remote Ceph OSD peer and needs no account, capabilities, or privileges on the victim Linux host; any kernel RBD client connected to a multi-tenant or attacker-controlled cluster is exposed when exclusive-lock recovery issues LIST_WATCHERS.\nUI:N - Once an RBD image with exclusive-lock is mapped, ceph_osdc_list_watchers() is invoked automatically during rbd_try_lock() lock-contention recovery; no additional victim user or administrator action is required at exploit time beyond the existing client session.\nS:U - The out-of-bounds read, attacker-sized heap allocation, and any resulting kernel memory corruption all occur within the victim host kernel Ceph client; the flaw does not cross VM, container, or IOMMU security boundaries.\nC:H - The missing bounds check causes a 4-byte out-of-bounds kernel memory read via ceph_decode_32() when p equals end; per kernel guidance any out-of-bounds read is rated High, and the attacker can place controlled bytes immediately past the validated boundary via outdata_len.\nI:H - The out-of-bounds or attacker-supplied num_watchers value is passed directly to kzalloc_objs(), giving the remote peer control over kernel heap allocation size and subsequent decode_watchers() processing of watcher structures in the RBD exclusive-lock path.\nA:H - The slab out-of-bounds read can trigger KASAN faults or kernel oops on instrumented builds, and a large attacker-chosen num_watchers can cause ENOMEM/OOM or stall the RBD lock worker during repeated decode_watcher() attempts, producing severe repeatable availability loss." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ceph/osd_client.c" ], "versions": [ { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "85479b7d65b4ebcb07fbbe57230976793974ab4a", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "1c824e7c75bb4adf19553dd4ea944a5d83096be8", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "f161be39201eb5f9b1f58fb8f90b8a9cd3931eb6", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "eab3eeb68bfc639d74f27256f05546af5c4f787d", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "c59219a6b62d74936963983e5815524c3de8dd79", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "cb8246e5846dbbe34930903a90c7a90dd8e5910b", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "7130d94846dadbb97b6b7f4d78a3a7bba6e3daa1", "status": "affected", "versionType": "git" }, { "version": "a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c", "lessThan": "00ead17c7de137a692edee59f2772e6af687e8eb", "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/osd_client.c" ], "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.267", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.218", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.154", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.106", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.47", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.10", "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": "5.10.267" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.15.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.6.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.106" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.1.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/85479b7d65b4ebcb07fbbe57230976793974ab4a" }, { "url": "https://git.kernel.org/stable/c/1c824e7c75bb4adf19553dd4ea944a5d83096be8" }, { "url": "https://git.kernel.org/stable/c/f161be39201eb5f9b1f58fb8f90b8a9cd3931eb6" }, { "url": "https://git.kernel.org/stable/c/eab3eeb68bfc639d74f27256f05546af5c4f787d" }, { "url": "https://git.kernel.org/stable/c/c59219a6b62d74936963983e5815524c3de8dd79" }, { "url": "https://git.kernel.org/stable/c/cb8246e5846dbbe34930903a90c7a90dd8e5910b" }, { "url": "https://git.kernel.org/stable/c/7130d94846dadbb97b6b7f4d78a3a7bba6e3daa1" }, { "url": "https://git.kernel.org/stable/c/00ead17c7de137a692edee59f2772e6af687e8eb" } ], "title": "libceph: fix OOB read in decode_watchers() via missing bounds check", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-80557", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:17:25.527528Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:26.946Z" } } ] } }