{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21832","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T08:45:45.777Z","datePublished":"2025-03-06T16:22:34.125Z","dateUpdated":"2026-08-05T11:54:48.618Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:54:48.618Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock: don't revert iter for -EIOCBQUEUED\n\nblkdev_read_iter() has a few odd checks, like gating the position and\ncount adjustment on whether or not the result is bigger-than-or-equal to\nzero (where bigger than makes more sense), and not checking the return\nvalue of blkdev_direct_IO() before doing an iov_iter_revert(). The\nlatter can lead to attempting to revert with a negative value, which\nwhen passed to iov_iter_revert() as an unsigned value will lead to\nthrowing a WARN_ON() because unroll is bigger than MAX_RW_COUNT.\n\nBe sane and don't revert for -EIOCBQUEUED, like what is done in other\nspots."}],"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 syscalls only — io_uring submission (or aio) of an O_DIRECT read against a block device file descriptor. There is no network-facing path into `blkdev_read_iter()`.\nAC:L - The attacker controls both sides of the race: setting `IOSQE_ASYNC` forces io-wq offload so the completion runs in parallel with the still-executing `blkdev_read_iter()`, and choosing a fast backing device (NVMe/brd/null_blk/loop) plus unbounded submission retries makes the window trivially winnable.\nPR:L - Only an unprivileged local account is needed, holding a readable block device node opened with O_DIRECT — commonly available via the disk/cdrom groups, udev uaccess on removable media, containers with device access, and embedded/automotive/IoT images where the application user has raw device access. No CAP_SYS_ADMIN or root is required.\nUI:N - The attacker submits the io_uring read entirely on their own; no victim action, mount, or file open by another user is involved.\nS:U - The freed object, the corruption, and the resulting impact are all within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free — `iov_iter_count()`/`iov_iter_revert()` read the recycled `io_async_rw` and walk backwards out of bounds through a freed or reused bvec/iovec array, and the resulting corrupted iter can be consumed by another in-flight request to DMA arbitrary kernel memory back to the attacker.\nI:H - `iov_iter_revert()` writes `count`, `iov_offset`, `nr_segs`, and the `bvec`/`__iov` pointer into freed/recycled heap memory with an attacker-influenced `unroll`, giving heap-spray-able corruption of a concurrently used iterator that is exploitable for out-of-bounds writes and control-flow hijacking.\nA:H - The reported symptom is a `WARN_ON()` in `iov_iter_revert()` (immediate panic under panic_on_warn), and for the common `ITER_UBUF`/xarray iters the same path hits an unconditional `BUG()`; the underlying use-after-free also crashes the kernel outright under KASAN or on heap corruption."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/fops.c"],"versions":[{"version":"3e1f941dd9f33776b3df4e30f741fe445ff773f3","lessThan":"6c26619effb1b4cb7d20b4e666ab8f71f6a53ccb","status":"affected","versionType":"git"},{"version":"3e1f941dd9f33776b3df4e30f741fe445ff773f3","lessThan":"84671b0630ccb46ae9f1f99a45c7d63ffcd6a474","status":"affected","versionType":"git"},{"version":"3e1f941dd9f33776b3df4e30f741fe445ff773f3","lessThan":"68f16d3034a06661245ecd22f0d586a8b4e7c473","status":"affected","versionType":"git"},{"version":"3e1f941dd9f33776b3df4e30f741fe445ff773f3","lessThan":"a58f136bad29f9ae721a29d98c042fddbee22f77","status":"affected","versionType":"git"},{"version":"3e1f941dd9f33776b3df4e30f741fe445ff773f3","lessThan":"b13ee668e8280ca5b07f8ce2846b9957a8a10853","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/fops.c"],"versions":[{"version":"5.17","status":"affected"},{"version":"0","lessThan":"5.17","status":"unaffected","versionType":"semver"},{"version":"6.1.129","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.78","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.14","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.3","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14","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":"5.17","versionEndExcluding":"6.1.129"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17","versionEndExcluding":"6.6.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17","versionEndExcluding":"6.12.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17","versionEndExcluding":"6.13.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17","versionEndExcluding":"6.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/6c26619effb1b4cb7d20b4e666ab8f71f6a53ccb"},{"url":"https://git.kernel.org/stable/c/84671b0630ccb46ae9f1f99a45c7d63ffcd6a474"},{"url":"https://git.kernel.org/stable/c/68f16d3034a06661245ecd22f0d586a8b4e7c473"},{"url":"https://git.kernel.org/stable/c/a58f136bad29f9ae721a29d98c042fddbee22f77"},{"url":"https://git.kernel.org/stable/c/b13ee668e8280ca5b07f8ce2846b9957a8a10853"}],"title":"block: don't revert iter for -EIOCBQUEUED","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T21:00:04.401Z"}}]}}