CVE-2026-98289

/// Technical description

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

af_unix: Unify scc_index when finalising SCC in __unix_walk_scc().

Commit bfdb01283ee8 ("af_unix: Assign a unique index to SCC.")

changed Tarjan's algorithm to update lowlink with lowlink,

which is called lowpoint (unix_vertex.scc_index).

unix_vertex_dead() assumes all vertices in an SCC share the same

lowpoint, but this is not always true if an SCC has two or more

back edges, depending on the order of DFS.

For example, the graph below has two back edges from B to A

and from C to B.

A --> B --> C

^ | ^ |

`----' `----'

If DFS walks through A -> B -> C -> B (-> C -> B) -> A (-> B -> A),

each index and scc_index will be updated as follows.

A --> B --> C C = (3, 3) (index, scc_index)

B = (2, 2)

A = (1, 1)

A ... B ... C C = (3, 2)<-.

^ | B = (2, 2) -'

`----' A = (1, 1)

A ... B ... C C = (3, 2)

^ | . . B = (2, 1)<

/// 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