CVE-2023-53593
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-04

Last updated on: 2026-03-21

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: cifs: Release folio lock on fscache read hit. Under the current code, when cifs_readpage_worker is called, the call contract is that the callee should unlock the page. This is documented in the read_folio section of Documentation/filesystems/vfs.rst as: > The filesystem should unlock the folio once the read has completed, > whether it was successful or not. Without this change, when fscache is in use and cache hit occurs during a read, the page lock is leaked, producing the following stack on subsequent reads (via mmap) to the page: $ cat /proc/3890/task/12864/stack [<0>] folio_wait_bit_common+0x124/0x350 [<0>] filemap_read_folio+0xad/0xf0 [<0>] filemap_fault+0x8b1/0xab0 [<0>] __do_fault+0x39/0x150 [<0>] do_fault+0x25c/0x3e0 [<0>] __handle_mm_fault+0x6ca/0xc70 [<0>] handle_mm_fault+0xe9/0x350 [<0>] do_user_addr_fault+0x225/0x6c0 [<0>] exc_page_fault+0x84/0x1b0 [<0>] asm_exc_page_fault+0x27/0x30 This requires a reboot to resolve; it is a deadlock. Note however that the call to cifs_readpage_from_fscache does mark the page clean, but does not free the folio lock. This happens in __cifs_readpage_from_fscache on success. Releasing the lock at that point however is not appropriate as cifs_readahead also calls cifs_readpage_from_fscache and *does* unconditionally release the lock after its return. This change therefore effectively makes cifs_readpage_worker work like cifs_readahead.
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Meta Information
Published
2025-10-04
Last Modified
2026-03-21
Generated
2026-06-16
AI Q&A
2025-10-04
EPSS Evaluated
2026-06-15
NVD
CVE-2023-53593
EUVD
EUVD-2025-32276
Affected Vendors & Products
Showing 15 associated CPEs
Vendor Product Version / Range
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 5.17
linux linux_kernel 6.5
linux linux_kernel 6.5
linux linux_kernel 6.5
linux linux_kernel 6.5
linux linux_kernel 6.5
linux linux_kernel 6.5
linux linux_kernel From 6.2 (inc) to 6.4.12 (exc)
linux linux_kernel From 5.17.1 (inc) to 6.1.47 (exc)
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability is in the Linux kernel's CIFS filesystem code. When using fscache, a cache hit during a read operation causes a page lock to be leaked because the code does not properly unlock the page after reading. This leads to a deadlock situation on subsequent reads to the same page, requiring a system reboot to resolve. The issue arises because the function cifs_readpage_worker does not release the folio lock as expected, unlike similar functions that do release it.

Impact Analysis

The vulnerability can cause a deadlock in the system when reading cached pages via CIFS with fscache enabled. This deadlock results from leaked page locks and can halt processes that try to access the affected pages, ultimately requiring a system reboot to recover. This can lead to system downtime and disruption of services relying on CIFS file access.

Detection Guidance

This vulnerability can be detected by observing a leaked page lock in the Linux kernel when using cifs with fscache. A symptom is a deadlock requiring a reboot. You can check the stack trace of a process experiencing the issue by running: cat /proc/<pid>/task/<tid>/stack and looking for the specific stack trace involving folio_wait_bit_common and filemap_read_folio as described. Replace <pid> and <tid> with the relevant process and thread IDs.

Mitigation Strategies

Immediate mitigation involves rebooting the affected system to resolve the deadlock caused by the leaked page lock. Applying the patch or update that fixes the cifs_readpage_worker to properly release the folio lock after a read operation is necessary to prevent recurrence.

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