CVE-2026-31597
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY filemap_fault() may drop the mmap_lock before returning VM_FAULT_RETRY, as documented in mm/filemap.c: "If our return…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY filemap_fault() may drop the mmap_lock before returning VM_FAULT_RETRY, as documented in mm/filemap.c: "If our return value has VM_FAULT_RETRY set, it's because the mmap_lock may be dropped before doing I/O or by lock_folio_maybe_drop_mmap()." When this happens, a concurrent munmap() can call remove_vma() and free the vm_area_struct via RCU. The saved 'vma' pointer in ocfs2_fault() then becomes a dangling pointer, and the subsequent trace_ocfs2_fault() call dereferences it -- a use-after-free. Fix this by saving ip_blkno as a plain integer before calling filemap_fault(), and removing vma from the trace event. Since ip_blkno is copied by value before the lock can be dropped, it remains valid regardless of what happens to the vma or inode afterward.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/35c2c05261d6f6d84aaa1355afa201d507943e76
- https://git.kernel.org/stable/c/36539c4d536f851a3b346a6ebb27b51bc3d77a94
- https://git.kernel.org/stable/c/3f5e74b5db9353b01ed50f4de84e75b755f8fbc2
- https://git.kernel.org/stable/c/4cf2768a0291a0cdd0dae801ea0eafa3878a349dPatch
- https://git.kernel.org/stable/c/6f072daefcab1d84ce37c073645615f63be91006Patch
- https://git.kernel.org/stable/c/76a602fdbb78dd05b2da06f74a988cebc97e82d0Patch
- https://git.kernel.org/stable/c/7de554cabf160e331e4442e2a9ad874ca9875921Patch
- https://git.kernel.org/stable/c/925bf22c1b823e231b1baea761fe8a1512e442f2Patch
- https://git.kernel.org/stable/c/d45ff441b416d4aa1af72b1db23d959601c04da2Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.