CVE-2026-93235
Low risk· EPSS 10%Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
A flaw was found in the Linux kernel F2FS filesystem where extending a file size across an unaligned EOF boundary did not zero out post-EOF data in the partial page. As a result, stale disk data beyond the previous EOF could be exposed after remounting or crash recovery.
Risk Assessment
Stale on-disk data beyond the previous EOF may leak into file contents visible to users, posing a confidentiality risk. This mainly affects environments other than Android, where direct PBA writes are restricted to pinfile.
Recommendation
Update the Linux kernel to a version containing the fix, and mount F2FS with the fsync_mode=strict option in environments exposed to this issue.
Other vulnerabilities in Linux kernel F2FS
See all- CVE-2026-89830Low risk· EPSS 10%
In the Linux kernel, __allocate_data_block() in the f2fs filesystem increments the valid block count via inc_valid_block_count() when allocating a new data block, but if the subsequent f2fs_allocate_data_block() fails, the function returns the error without rolling back that increment. This causes a permanent valid block count leak.
- CVE-2026-89829High
In the Linux kernel, f2fs_sanity_check_node_footer() is not passed the correct folio->index value, causing it to check the same nid incorrectly. This can lead to improper node consistency verification in the f2fs filesystem.
- CVE-2024-56692High
In the Linux kernel, the f2fs filesystem lacked a sanity check on the node block address (blkaddr) in truncate_node(). On a crafted filesystem image, a corrupted NAT entry can cause a kernel panic during block invalidation.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to zero post-EOF data when extending file size generic/794 4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad) --- tests/generic/794.out 2026-06-12 08:46:32.766426241 +0800 +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800 @@ -1,4 +1,16 @@ QA output created by 794 append_write +FAIL: non-zero data in gap [4080,4096) after shutdown+remount +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a >ZZZZZZZZZZZZZZZZ< +* +001000 truncate_up ... (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad' to see the entire diff) Ran: generic/794 Failures: generic/794 Failed 1 of 1 tests Steps of generic/794: 1. write 4096 bytes to file w/ 0x5a 2. use fiemap to get PBA of first block in file 3. truncate file to 4080 4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount 5. extend filesize via a) append 4096 from offset 4096, or b) truncate 8192, or c) fallocate 4096 from offset 4096 6. verify the gap is zeroed in memory [4080,4096) 7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown) 8. umount; mount; verify [4080,4096) is zeroed or not. When extending file size (e.g. via truncate, fallocate, or write) across an unaligned EOF boundary, we need to ensure that post-EOF data in the partial page is zeroed out in pagecache and marked dirty, then writeback the cache to persist zeroed data before committing inode w/ updated i_size. This help to prevent stale disk data beyond the previous EOF from being exposed after remounting or crash recovery. Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile, and pinfile has section-aligned filesize, so in Android, there should no problem, but for other usage in different environment, let's fix this w/ fsync_mode=strict mount option.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS