{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37779","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.940Z","datePublished":"2025-05-01T13:07:17.106Z","dateUpdated":"2026-08-05T11:57:30.683Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:57:30.683Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlib/iov_iter: fix to increase non slab folio refcount\n\nWhen testing EROFS file-backed mount over v9fs on qemu, I encountered a\nfolio UAF issue.  The page sanity check reports the following call trace. \nThe root cause is that pages in bvec are coalesced across a folio bounary.\nThe refcount of all non-slab folios should be increased to ensure\np9_releas_pages can put them correctly.\n\nBUG: Bad page state in process md5sum  pfn:18300\npage: refcount:0 mapcount:0 mapping:00000000d5ad8e4e index:0x60 pfn:0x18300\nhead: order:0 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0\naops:z_erofs_aops ino:30b0f dentry name(?):\"GoogleExtServicesCn.apk\"\nflags: 0x100000000000041(locked|head|node=0|zone=1)\nraw: 0100000000000041 dead000000000100 dead000000000122 ffff888014b13bd0\nraw: 0000000000000060 0000000000000020 00000000ffffffff 0000000000000000\nhead: 0100000000000041 dead000000000100 dead000000000122 ffff888014b13bd0\nhead: 0000000000000060 0000000000000020 00000000ffffffff 0000000000000000\nhead: 0100000000000000 0000000000000000 ffffffffffffffff 0000000000000000\nhead: 0000000000000010 0000000000000000 00000000ffffffff 0000000000000000\npage dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set\nCall Trace:\n dump_stack_lvl+0x53/0x70\n bad_page+0xd4/0x220\n __free_pages_ok+0x76d/0xf30\n __folio_put+0x230/0x320\n p9_release_pages+0x179/0x1f0\n p9_virtio_zc_request+0xa2a/0x1230\n p9_client_zc_rpc.constprop.0+0x247/0x700\n p9_client_read_once+0x34d/0x810\n p9_client_read+0xf3/0x150\n v9fs_issue_read+0x111/0x360\n netfs_unbuffered_read_iter_locked+0x927/0x1390\n netfs_unbuffered_read_iter+0xa2/0xe0\n vfs_iocb_iter_read+0x2c7/0x460\n erofs_fileio_rq_submit+0x46b/0x5b0\n z_erofs_runqueue+0x1203/0x21e0\n z_erofs_readahead+0x579/0x8b0\n read_pages+0x19f/0xa70\n page_cache_ra_order+0x4ad/0xb80\n filemap_readahead.isra.0+0xe7/0x150\n filemap_get_pages+0x7aa/0x1890\n filemap_read+0x320/0xc80\n vfs_read+0x6c6/0xa30\n ksys_read+0xf9/0x1c0\n do_syscall_64+0x9e/0x1a0\n entry_SYSCALL_64_after_hwframe+0x71/0x79"}],"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 triggered by local file I/O — an ordinary read()/readahead on a file-backed EROFS or loop-backed filesystem whose backing store lives on 9p/NFS/ceph — via the read/readahead syscall path, not by any remotely supplied data.\nAC:L - The only precondition is that a bvec entry spans a folio boundary, which the block layer's physical-contiguity merging (bvec_try_merge_page) produces routinely; the reporter hit it simply running md5sum, and an attacker can drive bulk readahead over large files to make it near-certain.\nPR:L - Any unprivileged local user who can read a file on the affected mount reaches the path; there is no capability check, credential check, or privileged ioctl anywhere between the read syscall and __iov_iter_get_pages_alloc().\nUI:N - No victim action is needed — the attacker's own read() on an already-mounted filesystem drives the entire path to completion.\nS:U - The refcount underflow and resulting folio use-after-free are confined to the kernel's own memory management; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The folio is freed to the buddy allocator while still in the page cache and still the target of in-flight I/O, so after reallocation the attacker reads back kernel or other-process data through the stale page-cache mapping — a UAF read primitive.\nI:H - I/O completion writes filesystem data into a page that has been freed and handed to another allocation, giving a controllable heap write primitive that is leverageable for corruption and control-flow hijack.\nA:H - The refcount underflow immediately produces \"Bad page state\"/bad_page reports and freeing of in-use, locked page-cache folios, leading to oops or panic; the inflated head-folio refcount additionally leaks memory permanently."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["lib/iov_iter.c"],"versions":[{"version":"b9c0e49abfca06f1a109acea834bcfc934f33f76","lessThan":"d833f21162c4d536d729628f8cf1ee8d4110f2b7","status":"affected","versionType":"git"},{"version":"b9c0e49abfca06f1a109acea834bcfc934f33f76","lessThan":"770c8d55c42868239c748a3ebc57c9e37755f842","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["lib/iov_iter.c"],"versions":[{"version":"6.14","status":"affected"},{"version":"0","lessThan":"6.14","status":"unaffected","versionType":"semver"},{"version":"6.14.4","lessThanOrEqual":"6.14.*","status":"unaffected","versionType":"semver"},{"version":"6.15","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":"6.14","versionEndExcluding":"6.14.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/d833f21162c4d536d729628f8cf1ee8d4110f2b7"},{"url":"https://git.kernel.org/stable/c/770c8d55c42868239c748a3ebc57c9e37755f842"}],"title":"lib/iov_iter: fix to increase non slab folio refcount","x_generator":{"engine":"bippy-1.2.0"}}}}