PT-2026-37385 · Linux · Linux

Published 2026-05-06 · Updated 2026-05-06 · CVE-2026-43075

Mitre

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix out-of-bounds write in ocfs2 write end inline

KASAN reports a use-after-free write of 4086 bytes in ocfs2 write end inline, called from ocfs2 write end nolock during a copy file range splice fallback on a corrupted ocfs2 filesystem mounted on a loop device. The actual bug is an out-of-bounds write past the inode block buffer, not a true use-after-free. The write overflows into an adjacent freed page, which KASAN reports as UAF.

The root cause is that ocfs2 try to write inline data trusts the on-disk id count field to determine whether a write fits in inline data. On a corrupted filesystem, id count can exceed the physical maximum inline data capacity, causing writes to overflow the inode block buffer.

Call trace (crash path):

vfs copy file range (fs/read write.c:1634) do splice direct splice direct to actor iter file splice write ocfs2 file write iter generic perform write ocfs2 write end ocfs2 write end nolock (fs/ocfs2/aops.c:1949) ocfs2 write end inline (fs/ocfs2/aops.c:1915) memcpy from folio <-- KASAN: write OOB

So add id count upper bound check in ocfs2 validate inode block() to alongside the existing i size check to fix it.

Related Identifiers

CVE-2026-43075

Affected Products

Linux

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-43075 · Security Note
• https://git.kernel.org/stable/c/69d3c69ade1e4285ab4ca48fe7acee0767e65604 · Note
• https://git.kernel.org/stable/c/e2c9dc6b6e96f3585f2a1062ca3374a52db0938f · Note
• https://git.kernel.org/stable/c/7bc5da4842bed3252d26e742213741a4d0ac1b14 · Note
• https://git.kernel.org/stable/c/947f953978b0d9463498d548d0f054f5a75be2e9 · Note
• https://git.kernel.org/stable/c/0c1af902223b6fcedb60904ca0b551254686c7b9 · Note