{"id":"CVE-2026-72372","state":"PUBLISHED","title":"afs: Fix lack of locking around modifications of net->cells_dyn_ino","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix lack of locking around modifications of net->cells_dyn_ino\n\nFix the lack of locking around modifications of net->cells_dyn_ino by\ntaking net->cells_lock exclusively.  This also requires to cell to be\nremoved from net->cells_dyn_ino in afs_destroy_cell_work() rather than in\nafs_cell_destroy() as the latter runs in RCU cleanup context and sleeping\nlocks cannot be taken there.","publishedAt":"2026-08-15T05:56:07.916Z","updatedAt":"2026-08-17T05:43:25.401Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"537b0105952578531f748c7fb3ce36ae9a514784","status":"affected","lessThan":"4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"2ffb70a8a01988046bb207b7d0af9358a8337378","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"e94f92fd56c553a8bf9421c3289e1b85c7c08857","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"55e841836c6f4646490f7b0347192b7a92d431ba","versionType":"git"},{"version":"6.12.97","status":"affected","lessThan":"6.12.101","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/dynroot.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/dynroot.c"]}],"references":["https://git.kernel.org/stable/c/4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b","https://git.kernel.org/stable/c/2ffb70a8a01988046bb207b7d0af9358a8337378","https://git.kernel.org/stable/c/e94f92fd56c553a8bf9421c3289e1b85c7c08857","https://git.kernel.org/stable/c/55e841836c6f4646490f7b0347192b7a92d431ba"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72372.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72372","state":"PUBLISHED","datePublished":"2026-08-15T05:56:07.916Z","dateUpdated":"2026-08-17T05:43:25.401Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.922Z"},"containers":{"cna":{"title":"afs: Fix lack of locking around modifications of net->cells_dyn_ino","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix lack of locking around modifications of net->cells_dyn_ino\n\nFix the lack of locking around modifications of net->cells_dyn_ino by\ntaking net->cells_lock exclusively.  This also requires to cell to be\nremoved from net->cells_dyn_ino in afs_destroy_cell_work() rather than in\nafs_cell_destroy() as the latter runs in RCU cleanup context and sleeping\nlocks cannot be taken there."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"537b0105952578531f748c7fb3ce36ae9a514784","status":"affected","lessThan":"4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"2ffb70a8a01988046bb207b7d0af9358a8337378","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"e94f92fd56c553a8bf9421c3289e1b85c7c08857","versionType":"git"},{"version":"1d0b929fc070b4115403a0a6206a0c6a62dd61f5","status":"affected","lessThan":"55e841836c6f4646490f7b0347192b7a92d431ba","versionType":"git"},{"version":"6.12.97","status":"affected","lessThan":"6.12.101","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/dynroot.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/dynroot.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b"},{"url":"https://git.kernel.org/stable/c/2ffb70a8a01988046bb207b7d0af9358a8337378"},{"url":"https://git.kernel.org/stable/c/e94f92fd56c553a8bf9421c3289e1b85c7c08857"},{"url":"https://git.kernel.org/stable/c/55e841836c6f4646490f7b0347192b7a92d431ba"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached only through local VFS operations on an AFS dynroot mount (getdents/readdir via afs_dynroot_readdir, lookup via afs_dynroot_lookup_cell) and cell create/destroy paths (afs_alloc_cell/afs_destroy_cell_work), not from remote AFS/RxRPC packet handling.\nAC:L - An attacker can reliably win the race by running concurrent threads that repeatedly readdir /afs while creating and expiring cells through lookups or /proc/net/afs/cells writes; syzbot and public PoCs reproduced the slab UAF within minutes without uncontrollable layout dependencies.\nPR:L - Exploitation requires only an unprivileged local user who can access a dynroot mount (typical world-readable /afs on AFS clients) or mount AFS with -o dyn inside a user namespace where CAP_SYS_ADMIN is available; real init-namespace root is not required.\nUI:N - No victim interaction is needed once dynroot is available; the attacker directly issues the readdir and cell-creation syscalls that race unsynchronized idr_alloc_cyclic, idr_remove, and idr_get_next on net->cells_dyn_ino.\nS:U - Impact is confined to kernel memory integrity and privilege boundaries within the host kernel; it does not cross VM, container, or IOMMU security scopes into a different authority.\nC:H - Concurrent idr_remove during afs_dynroot_readdir_cells leaves idr_get_next with a dangling afs_cell pointer, causing slab use-after-free reads of cell->name and cell->state (confirmed by KASAN in afs_dynroot_readdir) and enabling further kernel memory disclosure.\nI:H - IDR tree corruption and use-after-free of afs_cell objects provide attacker-influenced heap corruption primitives that can be developed into arbitrary kernel writes or control-flow hijack, not merely a benign error return.\nA:H - The race causes kernel oops/panic from corrupted IDR traversal or use-after-free during dir_emit; repeated triggering can crash or hang the system, satisfying high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:43:25.401Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.97","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}