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CVE-2023-53111 (GCVE-0-2023-53111)

Vulnerability from cvelistv5 – Published: 2025-05-02 15:55 – Updated: 2026-08-05 09:12
VLAI
Title
loop: Fix use-after-free issues
Summary
In the Linux kernel, the following vulnerability has been resolved: loop: Fix use-after-free issues do_req_filebacked() calls blk_mq_complete_request() synchronously or asynchronously when using asynchronous I/O unless memory allocation fails. Hence, modify loop_handle_cmd() such that it does not dereference 'cmd' nor 'rq' after do_req_filebacked() finished unless we are sure that the request has not yet been completed. This patch fixes the following kernel crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000054 Call trace: css_put.42938+0x1c/0x1ac loop_process_work+0xc8c/0xfd4 loop_rootcg_workfn+0x24/0x34 process_one_work+0x244/0x558 worker_thread+0x400/0x8fc kthread+0x16c/0x1e0 ret_from_fork+0x10/0x20
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6 , < 407badf73ec9fb0d5744bf2ca1745c1818aa222f (git)
Affected: bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6 , < e3fda704903f6d1fc351412f1bc6620333959ada (git)
Affected: bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6 , < 6917395c4667cfb607ed8bf1826205a59414657c (git)
Affected: bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6 , < 9b0cb770f5d7b1ff40bea7ca385438ee94570eec (git)
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Linux Linux Affected: 4.4
Unaffected: 0 , < 4.4 (semver)
Unaffected: 5.15.104 , ≤ 5.15.* (semver)
Unaffected: 6.1.21 , ≤ 6.1.* (semver)
Unaffected: 6.2.8 , ≤ 6.2.* (semver)
Unaffected: 6.3 , ≤ * (original_commit_for_fix)
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          "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 \u0027cmd\u0027 nor\n\u0027rq\u0027 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"
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              "value": "AV:L - The bug is in the loop block driver\u2019s 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\u2014no conditions outside attacker control.\nPR:L - LOOP_SET_FD/LOOP_CONFIGURE require no CAP_SYS_ADMIN\u2014only open access to the loop device node\u2014and 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\u2019s 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\u2019s crash (NULL deref in css_put from loop_process_work) shows a kernel oops/panic is readily achievable whenever the freed cmd is accessed."
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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\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: loop: Se corrigen los problemas de use after free. do_req_filebacked() llama a blk_mq_complete_request() de forma s\u00edncrona o as\u00edncrona al usar E/S as\u00edncrona, a menos que falle la asignaci\u00f3n de memoria. Por lo tanto, se debe modificar loop_handle_cmd() para que no desreferencia \u00abcmd\u00bb ni \u00abrq\u00bb tras la finalizaci\u00f3n de do_req_filebacked(), a menos que estemos seguros de que la solicitud a\u00fan no se ha completado. 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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:21:32+00:00",
      "cve": "CVE-2023-53111",
      "id": "CVE-2023-53111",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: loop: Fix use-after-free issues",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53111.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.