CVE-2026-63812: Linux

High severity, CVSS 7.8. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node() When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does not reset the length of the largest extent to 0 and update the inode folio. Since modifications to the extent tree are disallowed afterward, the cached largest extent may become stale. This can trigger the following error in xfstests generic/388: F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix In the f2fs_drop_inode path, __destroy_extent_node() does not need to guarantee that et->node_cnt is 0, because concurrency with writeback is expected in this path, and writeback may update the extent cache. This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback"), and remove the unnecessary zero check of et->node_cnt.

Affected products

• Linux Linux: from 6.6.140, before 6.6.144 (fixed in 6.6.144); from 6.12.88, before 6.12.95 (fixed in 6.12.95); from 6.18.30, before 6.18.38 (fixed in 6.18.38); from 7.0.7, before 7.1 (fixed in 7.1); from 7.1, before 7.1.3 (fixed in 7.1.3)

Published 2026-07-19. Last modified 2026-08-17.