{"id":"CVE-2023-53111","state":"PUBLISHED","title":"loop: Fix use-after-free issues","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nloop: Fix use-after-free issues\n\ndo_req_filebacked() calls blk_mq_complete_request() synchronously or\nasynchronously when using asynchronous I/O unless memory allocation fails.\nHence, modify loop_handle_cmd() such that it does not dereference 'cmd' nor\n'rq' after do_req_filebacked() finished unless we are sure that the request\nhas not yet been completed. This patch fixes the following kernel crash:\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000054\nCall trace:\n css_put.42938+0x1c/0x1ac\n loop_process_work+0xc8c/0xfd4\n loop_rootcg_workfn+0x24/0x34\n process_one_work+0x244/0x558\n worker_thread+0x400/0x8fc\n kthread+0x16c/0x1e0\n ret_from_fork+0x10/0x20","publishedAt":"2025-05-02T15:55:51.029Z","updatedAt":"2026-10-30T12:17:26.200Z","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":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"81bf9d78fa246a166619196ff5005430ed2bc7c2","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"407badf73ec9fb0d5744bf2ca1745c1818aa222f","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"e3fda704903f6d1fc351412f1bc6620333959ada","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"6917395c4667cfb607ed8bf1826205a59414657c","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"9b0cb770f5d7b1ff40bea7ca385438ee94570eec","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/loop.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.4","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.104","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.21","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.8","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/loop.c"]}],"references":["https://git.kernel.org/stable/c/81bf9d78fa246a166619196ff5005430ed2bc7c2","https://git.kernel.org/stable/c/407badf73ec9fb0d5744bf2ca1745c1818aa222f","https://git.kernel.org/stable/c/e3fda704903f6d1fc351412f1bc6620333959ada","https://git.kernel.org/stable/c/6917395c4667cfb607ed8bf1826205a59414657c","https://git.kernel.org/stable/c/9b0cb770f5d7b1ff40bea7ca385438ee94570eec"],"weaknesses":[],"ingestedAt":"2026-10-30T12:34:06.950Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53111.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53111","state":"PUBLISHED","datePublished":"2025-05-02T15:55:51.029Z","dateUpdated":"2026-10-30T12:17:26.200Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-05-02T15:51:43.554Z"},"containers":{"cna":{"title":"loop: Fix use-after-free issues","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nloop: Fix use-after-free issues\n\ndo_req_filebacked() calls blk_mq_complete_request() synchronously or\nasynchronously when using asynchronous I/O unless memory allocation fails.\nHence, modify loop_handle_cmd() such that it does not dereference 'cmd' nor\n'rq' after do_req_filebacked() finished unless we are sure that the request\nhas not yet been completed. This patch fixes the following kernel crash:\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000054\nCall trace:\n css_put.42938+0x1c/0x1ac\n loop_process_work+0xc8c/0xfd4\n loop_rootcg_workfn+0x24/0x34\n process_one_work+0x244/0x558\n worker_thread+0x400/0x8fc\n kthread+0x16c/0x1e0\n ret_from_fork+0x10/0x20"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"81bf9d78fa246a166619196ff5005430ed2bc7c2","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"407badf73ec9fb0d5744bf2ca1745c1818aa222f","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"e3fda704903f6d1fc351412f1bc6620333959ada","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"6917395c4667cfb607ed8bf1826205a59414657c","versionType":"git"},{"version":"bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6","status":"affected","lessThan":"9b0cb770f5d7b1ff40bea7ca385438ee94570eec","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/loop.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.4","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.104","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.21","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.8","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/block/loop.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/81bf9d78fa246a166619196ff5005430ed2bc7c2"},{"url":"https://git.kernel.org/stable/c/407badf73ec9fb0d5744bf2ca1745c1818aa222f"},{"url":"https://git.kernel.org/stable/c/e3fda704903f6d1fc351412f1bc6620333959ada"},{"url":"https://git.kernel.org/stable/c/6917395c4667cfb607ed8bf1826205a59414657c"},{"url":"https://git.kernel.org/stable/c/9b0cb770f5d7b1ff40bea7ca385438ee94570eec"}],"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 in the loop block driver’s I/O completion path (loop_handle_cmd), reached via local block I/O or loop ioctls on /dev/loop*, not by parsing remote network packets.\nAC:L - With LO_FLAGS_DIRECT_IO/AIO, lo_rw_aio can complete and free the request synchronously before do_req_filebacked() returns, so the subsequent cmd dereferences are a reliable UAF the attacker triggers by submitting I/O—no conditions outside attacker control.\nPR:L - LOOP_SET_FD/LOOP_CONFIGURE require no CAP_SYS_ADMIN—only open access to the loop device node—and LO_FLAGS_DIRECT_IO is a LOOP_CONFIGURE_SETTABLE_FLAGS bit; unprivileged users with device access (disk group, containers) or who can perform I/O on an already DIO-backed loop mount can reach the path.\nUI:N - The attacker configures the loop device (or uses an accessible one) and submits reads/writes themselves; no separate victim action is required.\nS:U - Impact is confined to the local kernel’s authority (crash or privilege escalation within the host); it does not cross a VM/IOMMU/sandbox boundary.\nC:H - Use-after-free of the blk-mq request PDU (loop_cmd) lets an attacker reclaim and control freed object contents, enabling information disclosure primitives from the corrupted state.\nI:H - The same UAF can be turned into strong integrity primitives (e.g., css_put on a reclaimed pointer, double completion via corrupted use_aio), supporting arbitrary write / control-flow hijack.\nA:H - The report’s crash (NULL deref in css_put from loop_process_work) shows a kernel oops/panic is readily achievable whenever the freed cmd is accessed."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:17:26.200Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"5.15.104"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.1.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.2.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4","versionEndExcluding":"6.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-53111","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T21:33:59.619907Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T21:41:27.021Z"}}]}}}