In the Linux kernel, the following vulnerability has been resolved:
udf: validate free block extents against the partition length
udffreeblocks() checks the logical block number and count against the partition length, but drops the extent offset from that final bound. A crafted extent can pass the guard while logicalBlockNum + offset + count points past the partition, which later indexes past the space bitmap array.
A single ftruncate(2) on a file backed by such an extent reliably panics the kernel. This is a local availability issue. On desktop systems where UDisks/polkit allows the active user to mount removable UDF media without CAPSYSADMIN, an unprivileged local user can supply the crafted filesystem and trigger the panic by truncating a writable file on it. Systems that require root or CAPSYSADMIN to mount the image have a higher prerequisite.
No confidentiality or integrity impact is claimed: the reproduced primitive is an out-of-bounds read of a bitmap pointer slot followed by a kernel panic.
Use the already computed logicalBlockNum + offset + count value for the partition length check. Also make loadblockbitmap() reject an out-of-range block group before indexing sblockbitmap[], so corrupted callers cannot walk past the flexible array.
{
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64324.json"
}