CVE-2026-64324

In the Linux kernel, the following vulnerability has been resolved: udf: validate free block extents against the partition length udf_free_blocks() 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 CAP_SYS_ADMIN, 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 CAP_SYS_ADMIN 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 load_block_bitmap() reject an out-of-range block group before indexing s_block_bitmap[], so corrupted callers cannot walk past the flexible array.

• linux linux kernel (>= 4.19.320 < 4.20) • linux linux kernel (>= 5.4.282 < 5.5) • linux linux kernel (>= 5.10.224 < 5.10.261) • linux linux kernel (>= 5.15.165 < 5.15.212) • linux linux kernel (>= 6.1.105 < 6.1.178) • linux linux kernel (>= 6.6.46 < 6.6.145) • linux linux kernel (>= 6.10.5 < 6.12.96) • linux linux kernel (>= 6.13 < 6.18.39) • linux linux kernel (>= 6.19 < 7.1.4)