Linux Kernel XFS Crash: NULL b_addr in xfs_buf_free
CVE-2026-74728 Published on August 22, 2026
xfs: handle NULL b_addr in xfs_buf_free
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.
Products Associated with CVE-2026-74728
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Affected Versions
Linux:- Version 5076a6040ca1613e616d84aecfaac5f932db84e0 and below ccf6738adcafa5ddbddc4e71b45d8a51b86643c7 is affected.
- Version 5076a6040ca1613e616d84aecfaac5f932db84e0 and below 3aa0c1d23ee1b9d9b340fb2f4736536e1408d706 is affected.
- Version 5076a6040ca1613e616d84aecfaac5f932db84e0 and below d852729c5f4f830fbe7413df032e29459b3daf83 is affected.
- Version 6.9 is affected.
- Before 6.9 is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.