The Linux kernel’s x86/fred interrupt handler contains an issue where the helper function array_index_nospec() is executed before an index value is stored on the stack, exposing a speculative value that should remain hidden. This can allow a side‑channel that leaks kernel data during speculative execution, without providing arbitrary code execution or direct compromise.

The flaw exists in the x86/fred code of every Linux kernel that has not applied the upstream patch identified in the advisory references. No specific distribution or vendor is listed beyond the generic Linux kernel; therefore any machine running a vulnerable kernel revision is a potential target.

The CVSS score of 5.5 indicates moderate severity. An EPSS score below 1% and absence from the CISA KEV catalog suggest a low likelihood of near‑term exploitation. The attack vector appears to require triggering the vulnerable interrupt path, likely from a local or privileged context, and would primarily provide speculative data leakage rather than full code execution.