CVE-2026-23224
Received Received - Intake
Use-After-Free Vulnerability in Linux Kernel EROFS DirectIO Mounts

Publication date: 2026-02-18

Last updated on: 2026-04-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: erofs: fix UAF issue for file-backed mounts w/ directio option [ 9.269940][ T3222] Call trace: [ 9.269948][ T3222] ext4_file_read_iter+0xac/0x108 [ 9.269979][ T3222] vfs_iocb_iter_read+0xac/0x198 [ 9.269993][ T3222] erofs_fileio_rq_submit+0x12c/0x180 [ 9.270008][ T3222] erofs_fileio_submit_bio+0x14/0x24 [ 9.270030][ T3222] z_erofs_runqueue+0x834/0x8ac [ 9.270054][ T3222] z_erofs_read_folio+0x120/0x220 [ 9.270083][ T3222] filemap_read_folio+0x60/0x120 [ 9.270102][ T3222] filemap_fault+0xcac/0x1060 [ 9.270119][ T3222] do_pte_missing+0x2d8/0x1554 [ 9.270131][ T3222] handle_mm_fault+0x5ec/0x70c [ 9.270142][ T3222] do_page_fault+0x178/0x88c [ 9.270167][ T3222] do_translation_fault+0x38/0x54 [ 9.270183][ T3222] do_mem_abort+0x54/0xac [ 9.270208][ T3222] el0_da+0x44/0x7c [ 9.270227][ T3222] el0t_64_sync_handler+0x5c/0xf4 [ 9.270253][ T3222] el0t_64_sync+0x1bc/0x1c0 EROFS may encounter above panic when enabling file-backed mount w/ directio mount option, the root cause is it may suffer UAF in below race condition: - z_erofs_read_folio wq s_dio_done_wq - z_erofs_runqueue - erofs_fileio_submit_bio - erofs_fileio_rq_submit - vfs_iocb_iter_read - ext4_file_read_iter - ext4_dio_read_iter - iomap_dio_rw : bio was submitted and return -EIOCBQUEUED - dio_aio_complete_work - dio_complete - dio->iocb->ki_complete (erofs_fileio_ki_complete()) - kfree(rq) : it frees iocb, iocb.ki_filp can be UAF in file_accessed(). - file_accessed : access NULL file point Introduce a reference count in struct erofs_fileio_rq, and initialize it as two, both erofs_fileio_ki_complete() and erofs_fileio_rq_submit() will decrease reference count, the last one decreasing the reference count to zero will free rq.
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Meta Information
Published
2026-02-18
Last Modified
2026-04-02
Generated
2026-06-16
AI Q&A
2026-02-18
EPSS Evaluated
2026-06-15
NVD
CVE-2026-23224
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.19 (inc) to 6.19.1 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.11 (exc)
linux linux_kernel From 6.12 (inc) to 6.12.72 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

This vulnerability is a Use-After-Free (UAF) issue in the Linux kernel's erofs filesystem when using file-backed mounts with the directio option enabled.

The problem occurs due to a race condition involving the submission and completion of bio requests during file read operations. Specifically, the bio is submitted and returns -EIOCBQUEUED, and when the asynchronous I/O completes, the kernel frees an I/O control block (iocb) structure prematurely.

As a result, the iocb's file pointer can become a dangling pointer, leading to a use-after-free scenario when the file is accessed later.

The fix introduced a reference count in the erofs_fileio_rq structure to ensure that the memory is only freed when it is safe to do so, preventing the UAF condition.

Impact Analysis

This vulnerability can cause system instability or crashes (kernel panics) when using the erofs filesystem with file-backed mounts and the directio option.

Because it is a use-after-free bug, it may potentially be exploited to execute arbitrary code or cause denial of service by crashing the system, depending on the attacker's capabilities and system configuration.

Compliance Impact

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Detection Guidance

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Mitigation Strategies

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