CVE-2023-52993 x86/i8259: Mark legacy PIC interrupts with IRQ_LEVEL
A NULL pointer dereference in the Linux kernel's legacy PIC interrupt handling can cause a system crash during kdump execution.
- 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-2023-52993?
CVE-2023-52993 is a medium-severity vulnerability in Linux kernel, published on 27 Mar 2025. 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:
x86/i8259: Mark legacy PIC interrupts with IRQ_LEVEL
Baoquan reported that after triggering a crash the subsequent crash-kernel fails to boot about half of the time. It triggers a NULL pointer dereference in the periodic tick code.
This happens because the legacy timer interrupt (IRQ0) is resent in software which happens in soft interrupt (tasklet) context. In this context get_irq_regs() returns NULL which leads to the NULL pointer dereference.
The reason for the resend is a spurious APIC interrupt on the IRQ0 vector which is captured and leads to a resend when the legacy timer interrupt is enabled. This is wrong because the legacy PIC interrupts are level triggered and therefore should never be resent in software, but nothing ever sets the IRQ_LEVEL flag on those interrupts, so the core code does not know about their trigger type.
Ensure that IRQ_LEVEL is set when the legacy PCI interrupts are set up.
Weakness: CWE-476
Which versions are affected by CVE-2023-52993?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-52993?
Apply the vendor's patch.
Is CVE-2023-52993 being exploited?
There is no known exploitation of CVE-2023-52993 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-52993, DEBIAN-CVE-2023-52993, GHSA-g7hp-hfwm-x3rp, UBUNTU-CVE-2023-52993.