CVE-2023-53826

/// Technical 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].

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References