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CVE-2024-26999

MEDIUMCVSS 5.5/10EPSS 0.18%

Last modified

CVE-2024-26999 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: serial/pmac_zilog: Remove flawed mitigation for rx irq flood The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmac_zilog as a serial console: ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0 That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). EPSS estimates a 0.18% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: serial/pmac_zilog: Remove flawed mitigation for rx irq flood The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmac_zilog as a serial console: ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0 That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uart_port. Even when it's not fatal, the serial port rx function ceases to work. Also, the iteration limit doesn't play nicely with QEMU, as can be seen in the bug report linked below. A web search for other reports of the error message "pmz: rx irq flood" didn't produce anything. So I don't think this code is needed any more. Remove it.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.18%

8.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 2.6.12, < 5.15.157—
LinuxLinux Kernel>= 5.16, < 6.1.88—
LinuxLinux Kernel>= 6.2, < 6.6.29—
LinuxLinux Kernel>= 6.7, < 6.8.8—
LinuxLinux Kernel6.9Rc1
DebianDebian Linux10.0—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2024-26999?
In the Linux kernel, the following vulnerability has been resolved: serial/pmac_zilog: Remove flawed mitigation for rx irq flood The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmac_zilog as a serial console: ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0 That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uart_port. Even when it's not fatal, the serial port rx function ceases to work. Also, the iteration limit doesn't play nicely with QEMU, as can be seen in the bug report linked below. A web search for other reports of the error message "pmz: rx irq flood" didn't produce anything. So I don't think this code is needed any more. Remove it.
How severe is CVE-2024-26999?
CVE-2024-26999 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2024-26999?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2024-26999?

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Source: NVD / NIST