CVE-2023-53826
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BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ubi: Fix UAF wear-leveling entry in eraseblk_count_seq_show() Wear-leveling entry could be freed in error path, which may be accessed again in eraseblk_count_seq_show(), for example: __erase_worker eraseblk_count_seq_show wl = ubi->lookuptbl[*block_number] if (wl) wl_entry_destroy ubi->lookuptbl[e->pnum] = NULL kmem_cache_free(ubi_wl_entry_slab, e) erase_count = wl->ec // UAF! Wear-leveling entry updating/accessing in ubi->lookuptbl should be protected by ubi->wl_lock, fix it by adding ubi->wl_lock to serialize wl entry accessing between wl_entry_destroy() and eraseblk_count_seq_show(). Fetch a reproducer in [Link].
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Meta Information
Published
2025-12-09
Last Modified
2025-12-09
Generated
2026-06-16
AI Q&A
2025-12-09
EPSS Evaluated
2026-06-14
NVD
CVE-2023-53826
EUVD
EUVD-2023-60170
Affected Vendors & Products
Currently, no data is known.
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability is a Use-After-Free (UAF) issue in the Linux kernel's UBI (Unsorted Block Images) subsystem related to wear-leveling entries. Specifically, a wear-leveling entry could be freed in an error path but still accessed afterward in the eraseblk_count_seq_show() function, leading to potential invalid memory access. The problem arises because the updating and accessing of wear-leveling entries in the lookuptbl were not properly synchronized with a lock (ubi->wl_lock). The fix involved adding this lock to serialize access and prevent the use-after-free condition.

Impact Analysis

This vulnerability can lead to use-after-free conditions in the Linux kernel, which may cause system instability, crashes, or potentially allow an attacker to execute arbitrary code or escalate privileges if they can trigger the flaw. It affects the reliability and security of systems running vulnerable Linux kernel versions with UBI wear-leveling enabled.

Mitigation Strategies

Apply the patch that fixes the use-after-free (UAF) vulnerability in the Linux kernel's ubi wear-leveling entry by ensuring that ubi->wl_lock is used to serialize access between wl_entry_destroy() and eraseblk_count_seq_show(). This prevents concurrent access issues. Updating your Linux kernel to a version that includes this fix is the recommended mitigation.

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