{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53111", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-05-02T15:51:43.554Z", "datePublished": "2025-05-02T15:55:51.029Z", "dateUpdated": "2026-08-05T09:12:50.996Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:12:50.996Z" }, "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" } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/block/loop.c" ], "versions": [ { "version": "bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6", "lessThan": "407badf73ec9fb0d5744bf2ca1745c1818aa222f", "status": "affected", "versionType": "git" }, { "version": "bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6", "lessThan": "e3fda704903f6d1fc351412f1bc6620333959ada", "status": "affected", "versionType": "git" }, { "version": "bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6", "lessThan": "6917395c4667cfb607ed8bf1826205a59414657c", "status": "affected", "versionType": "git" }, { "version": "bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6", "lessThan": "9b0cb770f5d7b1ff40bea7ca385438ee94570eec", "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/loop.c" ], "versions": [ { "version": "4.4", "status": "affected" }, { "version": "0", "lessThan": "4.4", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.104", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.21", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2.8", "lessThanOrEqual": "6.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.3", "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": "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" } ] } ] } ], "references": [ { "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" } ], "title": "loop: Fix use-after-free issues", "x_generator": { "engine": "bippy-1.2.0" } } } }