CVE-2026-74728 xfs: handle NULL b_addr in xfs_buf_free
A null pointer dereference in the Linux kernel XFS filesystem can cause a system crash when buffer allocation fails, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74728?
CVE-2026-74728 is a vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
xfs: handle NULL b_addr in xfs_buf_free
When xfs_buf_alloc_backing_mem() fails, xfs_buf_free() is called with bp->b_addr still NULL. The code falls through to the folio_put path which calls virt_to_folio(NULL), dereferencing an invalid address and causing a kernel crash.
Call Trace: xfs_buf_free+0x25f/0x510 xfs_buf_alloc+0xc98/0x19b0 xfs_buf_find_insert+0x55/0x14d0 xfs_buf_get_map+0x122b/0x17c0 xfbtree_init_leaf_block+0x11c/0x4a0 xfbtree_init+0x1bb/0x460 xrep_rmap_setup_scan+0x100/0x1f0 xrep_rmapbt+0x41/0xc0
Fix this by skipping folio_put() when bp->b_addr is NULL.
Which versions are affected by CVE-2026-74728?
How do I fix CVE-2026-74728?
Apply the vendor's patch.
Is CVE-2026-74728 being exploited?
There is no known exploitation of CVE-2026-74728 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74728, DEBIAN-CVE-2026-74728, GHSA-rrpq-4xmf-c84j, UBUNTU-CVE-2026-74728.