CVE-2026-98629

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net/sched: cls_u32: fix manual hash table handle IDR aliasing

A u32 hash table created with an explicit handle ('tc filter add ...

handle 801: u32 divisor N') keys its IDR entry on the raw handle, while

the destroy paths free it under handle2id(handle). The two key domains

disagree for handles in the 0x800..0xFFF htid range:

handle2id() folds them back into the auto-allocated id space (1..0x7FF).

A manual table therefore leaves its raw-keyed IDR entry unreachable on

delete (a permanent leak), and its delete can drop the idr entry of an

unrelated live auto table. A later auto allocation can then hand out a

handle that aliases the live manual table; u32_lookup_ht() first-match

routes lookups and TCA_U32_LINK for that htid to the wrong table.

Key the divisor-path alloc on handle2id(handle) so allocation and

removal share one key domain. A manual handle that maps onto an id

already in use is rejected with -ENOSPC, and

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References