CVE-2025-39781

What it actually does

Removes an occasionally triggering WARN_ON_ONCE() call in the PA-RISC flush_cache_vmap function during virtual memory mapping operations in the Linux kernel.

Why it matters to the business

Spurious kernel warnings on affected PA-RISC hardware can consume unnecessary administrator time reviewing logs; no security exposure or service disruption results from the warning.

How an attack unfolds

No exploitation is possible; the change resolves a non-security logging issue rather than a code path that could be abused for unauthorized access or privilege escalation.

How to fix it

Update the Linux kernel to version 6.6.103 or apply commit 69cf90e5aa50fe3cb0c1a63cabc4761db44b0035; apply the corresponding fixed versions (0) for the listed MinimOS packages.

How to confirm the fix worked

Confirm the running kernel reports version 6.6.103 or later and inspect the flush_cache_vmap source to verify removal of the WARN_ON_ONCE call.

How to detect it

No active exploitation indicators exist; historical kernel logs may be reviewed for the original warning string if needed for auditing purposes.

What your security team should do

• Apply the kernel update on any PA-RISC systems running affected versions.
• Review kernel log monitoring rules to suppress or ignore the now-removed warning if still present in legacy environments.