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PatchSiren cyber security CVE debrief

CVE-2026-53388 Linux CVE debrief

A use-after-free vulnerability was found in the Linux kernel's fuse subsystem. The issue arises from fuse_try_move_folio() unlocking the request on entry but failing to re-lock it on the success path. This allows fuse_chan_abort() to end the request and free the fuse_io_args while the subsequent copy chain logic accesses the fuse_io_args, leading to use-after-free issues. The fix involves calling lock_request() before replace_page_cache_folio() to ensure the request remains locked on the success path.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

Linux kernel developers and maintainers, Linux distribution vendors, and users of Linux-based systems should be aware of this vulnerability and its potential impact on system stability and security.

Technical summary

The vulnerability is caused by a missing lock in the fuse_try_move_folio() function. When fuse_try_move_folio() unlocks the request on entry but does not re-lock it on the success path, it creates a window for fuse_chan_abort() to end the request and free the fuse_io_args. This can lead to use-after-free issues when the subsequent copy chain logic accesses the fuse_io_args. The fix ensures that the request is re-locked before replacing the page cache folio, preventing the fuse_io_args from being freed prematurely.

Defensive priority

Medium

Recommended defensive actions

  • Review and apply the provided kernel patches to ensure the fuse subsystem is properly locking requests.
  • Monitor Linux kernel updates and apply patches promptly.
  • Consider implementing additional monitoring and logging to detect potential exploitation attempts.
  • Perform a thorough review of system configurations and asset inventories to identify potential exposures.
  • Establish a rollback change window to minimize downtime in case of patch application issues.
  • Track and verify the effectiveness of implemented compensating controls.
  • Implement source tracking to monitor for similar vulnerabilities in the future.

Evidence notes

The CVE record was published on 2026-07-19T12:16:49.757Z and has not been modified since then. The NVD entry is currently Received. Multiple source references are provided, including kernel.org links to specific commits.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T12:16:49.757Z and has not been modified since then.