CVE-2026-98872: freevxfs: don't BUG() on unknown typed-extent type
In the Linux kernel, the following vulnerability has been resolved:
freevxfs: don't BUG() on unknown typed-extent type
vxfsbmaptyped() handles four typed-extent types and calls BUG() in its default case, so an on-disk typed extent with any other type value crashes the kernel. It is reachable from ioctl(FIBMAP) on a regular file:
kernel BUG at fs/freevxfs/vxfsbmap.c:230! RIP: vxfsbmaptyped fs/freevxfs/vxfsbmap.c:230 [inline] vxfsbmap1+0x128a/0x12d0 fs/freevxfs/vxfsbmap.c:257
Replace the BUG() with WARNONONCE() and return 0 -- the value vxfsbmaptyped() already returns on failure (and from the DEV4 case above); vxfsgetblk() maps 0 to -EIO, so the ioctl fails cleanly.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
In freevxfs vxfs_bmap_typed(), replace the BUG() in the default case for an unknown typed-extent type with WARN_ON_ONCE() and return 0, allowing vxfs_getblk() to map the result to -EIO so ioctl(FIBMAP) fails cleanly.