{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-50517", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-07T15:15:38.662Z", "datePublished": "2025-10-07T15:19:12.344Z", "dateUpdated": "2026-08-05T08:59:01.931Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:59:01.931Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: do not clobber swp_entry_t during THP split\n\nThe following has been observed when running stressng mmap since commit\nb653db77350c (\"mm: Clear page->private when splitting or migrating a page\")\n\n watchdog: BUG: soft lockup - CPU#75 stuck for 26s! [stress-ng:9546]\n CPU: 75 PID: 9546 Comm: stress-ng Tainted: G E 6.0.0-revert-b653db77-fix+ #29 0357d79b60fb09775f678e4f3f64ef0579ad1374\n Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016\n RIP: 0010:xas_descend+0x28/0x80\n Code: cc cc 0f b6 0e 48 8b 57 08 48 d3 ea 83 e2 3f 89 d0 48 83 c0 04 48 8b 44 c6 08 48 89 77 18 48 89 c1 83 e1 03 48 83 f9 02 75 08 <48> 3d fd 00 00 00 76 08 88 57 12 c3 cc cc cc cc 48 c1 e8 02 89 c2\n RSP: 0018:ffffbbf02a2236a8 EFLAGS: 00000246\n RAX: ffff9cab7d6a0002 RBX: ffffe04b0af88040 RCX: 0000000000000002\n RDX: 0000000000000030 RSI: ffff9cab60509b60 RDI: ffffbbf02a2236c0\n RBP: 0000000000000000 R08: ffff9cab60509b60 R09: ffffbbf02a2236c0\n R10: 0000000000000001 R11: ffffbbf02a223698 R12: 0000000000000000\n R13: ffff9cab4e28da80 R14: 0000000000039c01 R15: ffff9cab4e28da88\n FS: 00007fab89b85e40(0000) GS:ffff9cea3fcc0000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007fab84e00000 CR3: 00000040b73a4003 CR4: 00000000003706e0\n DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n Call Trace:\n \n xas_load+0x3a/0x50\n __filemap_get_folio+0x80/0x370\n ? put_swap_page+0x163/0x360\n pagecache_get_page+0x13/0x90\n __try_to_reclaim_swap+0x50/0x190\n scan_swap_map_slots+0x31e/0x670\n get_swap_pages+0x226/0x3c0\n folio_alloc_swap+0x1cc/0x240\n add_to_swap+0x14/0x70\n shrink_page_list+0x968/0xbc0\n reclaim_page_list+0x70/0xf0\n reclaim_pages+0xdd/0x120\n madvise_cold_or_pageout_pte_range+0x814/0xf30\n walk_pgd_range+0x637/0xa30\n __walk_page_range+0x142/0x170\n walk_page_range+0x146/0x170\n madvise_pageout+0xb7/0x280\n ? asm_common_interrupt+0x22/0x40\n madvise_vma_behavior+0x3b7/0xac0\n ? find_vma+0x4a/0x70\n ? find_vma+0x64/0x70\n ? madvise_vma_anon_name+0x40/0x40\n madvise_walk_vmas+0xa6/0x130\n do_madvise+0x2f4/0x360\n __x64_sys_madvise+0x26/0x30\n do_syscall_64+0x5b/0x80\n ? do_syscall_64+0x67/0x80\n ? syscall_exit_to_user_mode+0x17/0x40\n ? do_syscall_64+0x67/0x80\n ? syscall_exit_to_user_mode+0x17/0x40\n ? do_syscall_64+0x67/0x80\n ? do_syscall_64+0x67/0x80\n ? common_interrupt+0x8b/0xa0\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe problem can be reproduced with the mmtests config\nconfig-workload-stressng-mmap. It does not always happen and when it\ntriggers is variable but it has happened on multiple machines.\n\nThe intent of commit b653db77350c patch was to avoid the case where\nPG_private is clear but folio->private is not-NULL. However, THP tail\npages uses page->private for \"swp_entry_t if folio_test_swapcache()\" as\nstated in the documentation for struct folio. This patch only clobbers\npage->private for tail pages if the head page was not in swapcache and\nwarns once if page->private had an unexpected value." } ], "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 through local memory-management paths (madvise pageout/cold, reclaim, migration) that split anonymous THPs after they are in the swap cache; it is not reachable from the network stack or remote protocols.\nAC:L - An unprivileged attacker who can allocate THPs and force reclaim/split (e.g., MADV_PAGEOUT, memory pressure, partial THP unmap) controls the triggering conditions; clobbering swp_entry_t on split is deterministic once a swapcached THP is split, and retries remove remaining timing noise.\nPR:L - Ordinary unprivileged local users can create anonymous THP mappings and invoke madvise(MADV_PAGEOUT/MADV_COLD) on their own VMAs without capabilities; only process_madvise on other tasks needs CAP_SYS_NICE.\nUI:N - Exploitation requires no victim action; the attacker performs the memory allocation and madvise/reclaim operations themselves.\nS:U - Impact stays within the host kernel's memory-management authority (local DoS / potential privilege impact on the same kernel); it is not a VM escape or other cross-authority boundary bypass.\nC:H - Zeroing tail-page swp_entry_t corrupts swap-cache bookkeeping so later delete/reclaim uses the wrong swap offset, leaving stale folio pointers in the swap xarray and enabling use-after-free / cross-process swap-data exposure.\nI:H - The same metadata corruption can remove or free the wrong swap-cache entries and swap slots, yielding heap UAF and arbitrary kernel memory-corruption primitives beyond a clean crash.\nA:H - The observed failure is a soft lockup in xas_descend during swap reclaim, and the corrupted swap-cache state can hang or crash the kernel under continued memory pressure." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/huge_memory.c" ], "versions": [ { "version": "b653db77350c7307a513b81856fe53e94cf42446", "lessThan": "8cace0eeb03d6043827faa6cf6c9067a9f05cd9f", "status": "affected", "versionType": "git" }, { "version": "b653db77350c7307a513b81856fe53e94cf42446", "lessThan": "71e2d666ef85d51834d658830f823560c402b8b6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/huge_memory.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.0.7", "lessThanOrEqual": "6.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1", "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": "5.19", "versionEndExcluding": "6.0.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/8cace0eeb03d6043827faa6cf6c9067a9f05cd9f" }, { "url": "https://git.kernel.org/stable/c/71e2d666ef85d51834d658830f823560c402b8b6" } ], "title": "mm/huge_memory: do not clobber swp_entry_t during THP split", "x_generator": { "engine": "bippy-1.2.0" } } } }