{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37906","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.966Z","datePublished":"2025-05-20T15:21:39.633Z","dateUpdated":"2026-08-05T11:58:13.306Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:58:13.306Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd\n\nublk_cancel_cmd() calls io_uring_cmd_done() to complete uring_cmd, but\nwe may have scheduled task work via io_uring_cmd_complete_in_task() for\ndispatching request, then kernel crash can be triggered.\n\nFix it by not trying to canceling the command if ublk block request is\nstarted."}],"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 race is reached only through local interfaces — `/dev/ublk-control` and `/dev/ublkc*` io_uring passthrough commands plus block I/O to `/dev/ublkb*`. There is no remote or adjacent-network path into ublk_drv.\nAC:L - The attacker owns both sides of the race: one thread submits I/O to the ublk block device (queueing `ublk_cmd_tw_cb` task work) while another tears down the io_uring ring or issues `UBLK_CMD_STOP_DEV`, driving `ublk_cancel_cmd()`. The window can be hit repeatedly in a loop with high queue depth until it lands.\nPR:L - ublk explicitly supports `UBLK_F_UNPRIVILEGED_DEV`, where `ublk_ctrl_add_dev()` accepts non-`CAP_SYS_ADMIN` callers and all later control commands gate only on file permissions of `/dev/ublkc*`, so an ordinary local user (including inside a container) can create and drive the device. Only basic local-user access is needed, not real root.\nUI:N - The attacking process performs every step itself — creating the ublk device, issuing I/O, and triggering cancellation. No victim action or interaction is required.\nS:U - The corruption is confined to kernel heap objects (`io_kiocb`) within the same security authority; the ublk driver and io_uring both run in the kernel's own scope. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed io_uring request is dereferenced and re-completed, so an attacker who reclaims the slab object controls its contents and can have kernel data posted back through the CQE and the ublk io path. Per UAF guidance this constitutes a path to arbitrary kernel memory disclosure.\nI:H - The second `io_uring_cmd_done()` writes result fields into and relinks a freed `io_kiocb`, and the request is freed twice — a write-after-free plus double-free on a well-known io_uring slab that is a standard heap-spray target for control-flow hijack. This is high-integrity memory corruption, not a bounded write.\nA:H - The commit states plainly that \"kernel crash can be triggered,\" and the double completion corrupts io_uring's completion/task-work lists. Any unprivileged local user with a ublk device can panic the machine on demand."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/ublk_drv.c"],"versions":[{"version":"216c8f5ef0f209a3797292c487bdaa6991ab4b92","lessThan":"fb2eb9ddf556f93fef45201e1f9d2b8674bcc975","status":"affected","versionType":"git"},{"version":"216c8f5ef0f209a3797292c487bdaa6991ab4b92","lessThan":"f40139fde5278d81af3227444fd6e76a76b9506d","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/ublk_drv.c"],"versions":[{"version":"6.7","status":"affected"},{"version":"0","lessThan":"6.7","status":"unaffected","versionType":"semver"},{"version":"6.14.6","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":"6.7","versionEndExcluding":"6.14.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/fb2eb9ddf556f93fef45201e1f9d2b8674bcc975"},{"url":"https://git.kernel.org/stable/c/f40139fde5278d81af3227444fd6e76a76b9506d"}],"title":"ublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd","x_generator":{"engine":"bippy-1.2.0"}}}}