The kernel’s TCP‑Authenticated‑Over stack compares Message Authentication Codes (MACs) using a routine that can reveal timing information, creating a side‑channel that could let a remote attacker infer the correct MAC by measuring packet processing time. This inference is based on the described mitigation of timing attacks and the nature of MAC comparisons. The patch replaces the non‑constant‑time logic with a constant‑time helper function, eliminating the leakage and mitigating a potential timing side‑channel, classified as CWE‑208.

All Linux kernel releases that include TCP‑AO, as indicated by the supplied CPEs, are affected. No specific kernel versions are listed, so any installation where TCP‑AO is enabled is potentially vulnerable.

The CVSS score of 9.8 signals a severe vulnerability, but the EPSS score of less than 1% indicates a very low probability of public exploitation. The vulnerability is not in the CISA KEV catalog, so no widespread attacks are documented. A likely exploitation scenario would involve a remote attacker sending crafted packets to a host with TCP‑AO enabled and performing precise timing analysis of packet handling durations.