F5-K000163547: Medium severity F5 F5OS vulnerability
In the Linux kernel, the following vulnerability has been resolved: udf: fix partition descriptor append bookkeeping Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in partdescsloc[]. handlepartitiondescriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and numpartdescs keeps growing. Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by numpartdescs. If partnum is already aligned to PARTDESCALLOCSTEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table. Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 2.0.0- - Compensating control
In the Linux kernel UDF partition descriptor append logic, store partnum in each appended slot and size table growth from the next append count (num_part_descs) rather than partnum, so deduplication and capacity tracking remain consistent and part_descs_loc[] cannot be overrun.