Bug 2492855 (CVE-2026-53272)

Summary: CVE-2026-53272 kernel: erofs: fix use-after-free on sbi->sync_decompress
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2026-06-25 10:09:13 UTC
In the Linux kernel, the following vulnerability has been resolved:

erofs: fix use-after-free on sbi->sync_decompress

z_erofs_decompress_kickoff() can race with filesystem unmount, causing
a use-after-free on sbi->sync_decompress.

When I/O completes, z_erofs_endio() calls z_erofs_decompress_kickoff()
to queue z_erofs_decompressqueue_work() asynchronously. Then, after all
folios are unlocked, unmount workflow can proceed and sbi will be freed
before accessing to sbi->sync_decompress.

Thread (unmount)        I/O completion        kworker
                        queue_work
                                              z_erofs_decompressqueue_work
                                               (all folios are unlocked)
cleanup_mnt
 ..
 erofs_kill_sb
  erofs_sb_free
   kfree(sbi)
                        access sbi->sync_decompress  // UAF!!