CVE-2026-53388: fuse: re-lock request before replacing page cache folio

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-19 · updated 2026-10-19
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: fuse: re-lock request before replacing page cache folio fuse_try_move_folio() unlocks the request on entry but does not re-lock it on the success path. This means fuse_chan_abort() can end the request and free the fuse_io_args (eg fuse_readpages_end()) while the subsequent copy chain logic after fuse_try_move_folio() accesses the fuse_io_args, leading to use-after-free issues. Fix this by calling lock_request() before replace_page_cache_folio(). This ensures the request is locked on the success path which will prevent the fuse_io_args from being freed while the later copying logic runs, and also ensures that the ap->folios[i]->mapping is never null since ap->folios[i] will always point to the newfolio after replace_page_cache_folio().

Affected products

Linux kernel: from 2.6.35 before 5.15.211; from 5.16 before 6.1.177; from 6.2 before 6.6.144; from 6.7 before 6.12.95; from 6.13 before 6.18.37; from 6.19 before 7.0.14 — fixed in 5.15.211, 6.1.177, 6.12.95, 6.18.37, 6.6.144, 7.0.14

How to fix

Upgrade to a fixed version: Linux kernel 5.15.211, 6.1.177, 6.12.95, 6.18.37. Check the vendor advisory for mitigations.

References

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