GHSA-f88f-286j-xf6gHighCVSS 7.8

In the Linux kernel, the following vulnerability has been resolved: fs: jfs: fix shift-out-of...

Published
October 22, 2025
Last Modified
August 4, 2026

🔗 CVE IDs covered (1)

📋 Description

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

fs: jfs: fix shift-out-of-bounds in dbAllocAG

Syzbot found a crash : UBSAN: shift-out-of-bounds in dbAllocAG. The underlying bug is the missing check of bmp->db_agl2size. The field can be greater than 64 and trigger the shift-out-of-bounds.

Fix this bug by adding a check of bmp->db_agl2size in dbMount since this field is used in many following functions. The upper bound for this field is L2MAXL2SIZE - L2MAXAG, thanks for the help of Dave Kleikamp. Note that, for maintenance, I reorganized error handling code of dbMount.

🔗 References (11)