CVE-2026-43211 PCI: Fix pci_slot_trylock() error handling
A logic error in Linux kernel PCI slot locking causes incorrect unlock operations, potentially leading to system instability or denial of service.
- 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-2026-43211?
CVE-2026-43211 is a high-severity vulnerability in Linux kernel, published on 6 May 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:
PCI: Fix pci_slot_trylock() error handling
Commit a4e772898f8b ("PCI: Add missing bridge lock to pci_bus_lock()") delegates the bridge device's pci_dev_trylock() to pci_bus_trylock() in pci_slot_trylock(), but it forgets to remove the corresponding pci_dev_unlock() when pci_bus_trylock() fails.
Before a4e772898f8b, the code did:
if (!pci_dev_trylock(dev)) /* <- lock bridge device */ goto unlock; if (dev->subordinate) { if (!pci_bus_trylock(dev->subordinate)) { pci_dev_unlock(dev); /* <- unlock bridge device */ goto unlock; } }
After a4e772898f8b the bridge-device lock is no longer taken, but the pci_dev_unlock(dev) on the failure path was left in place, leading to the bug.
This yields one of two errors:
1. A warning that the lock is being unlocked when no one holds it. 2. An incorrect unlock of a lock that belongs to another thread.
Fix it by removing the now-redundant pci_dev_unlock(dev) on the failure path.
[Same patch later posted by Keith at https://patch.msgid.link/[email protected]]
Weakness: CWE-667
Which versions are affected by CVE-2026-43211?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43211?
Apply the vendor's patch.
Is CVE-2026-43211 being exploited?
There is no known exploitation of CVE-2026-43211 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43211, DEBIAN-CVE-2026-43211, GHSA-3629-447p-wp7v, ROOT-OS-DEBIAN-11-CVE-2026-43211, ROOT-OS-UBUNTU-2204-CVE-2026-43211, ROOT-OS-UBUNTU-2404-CVE-2026-43211 and 1 more.