CVE-2026-31567 PM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask()
A spurious warning in the Linux kernel power management code can cause log spam or potential system instability during hibernation operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31567?
CVE-2026-31567 is a medium-severity denial of service vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
PM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask()
Commit 35e4a69b2003f ("PM: sleep: Allow pm_restrict_gfp_mask() stacking") introduced refcount-based GFP mask management that warns when pm_restore_gfp_mask() is called with saved_gfp_count == 0.
Some hibernation paths call pm_restore_gfp_mask() defensively where the GFP mask may or may not be restricted depending on the execution path. For example, the uswsusp interface invokes it in SNAPSHOT_CREATE_IMAGE, SNAPSHOT_UNFREEZE, and snapshot_release(). Before the stacking change this was a silent no-op; it now triggers a spurious WARNING.
Remove the WARN_ON() wrapper from the !saved_gfp_count check while retaining the check itself, so that defensive calls remain harmless without producing false warnings.
[ rjw: Subject tweak ]
Weakness: CWE-617
Which versions are affected by CVE-2026-31567?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31567?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-31567 being exploited?
There is no known exploitation of CVE-2026-31567 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31567, DEBIAN-CVE-2026-31567, GHSA-mxfm-927r-8r7x, UBUNTU-CVE-2026-31567.