high CVSS 7.8

CVE-2024-56699·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: s390/pci: Fix potential double remove of hotplug slot In commit 6ee600bfbe0f ("s390/pci: remove hotplug slot when releasing the device") the zpci_exit_slot() was moved from zpci_device_reserved() to zpci_release_device() with the intention of keeping the hotplug slot around until the device is actually removed. Now zpci_release_device() is only called once all references are dropped. Since the zPCI subsystem only drops its reference once the device is in the reserved state it follows that zpci_release_device() must only deal with devices in the reserved state. Despite that it contains code to tear down from both configured and standby state. For the standby case this already includes the removal of the hotplug slot so would cause a double removal if a device was ever removed in either configured or standby state. Instead of causing a potential double removal in a case that should never happen explicitly WARN_ON() if a device in non-reserved state is released and get rid of the dead code cases.

Severity: high
Software: Kernel
Fixed in: 6.12.2
Published: 2024-12-28

Affected versions

From: 6.12

Until: 6.12.2

Fixed in: 6.12.2

How to fix this CVE

Update your Linux kernel to version 6.12.2 or later to resolve this s390 PCI hotplug slot double-removal vulnerability. This fix prevents a potential kernel crash when PCI devices are removed in certain states on IBM System z platforms. Apply the kernel update through your distribution's package manager and reboot to activate the patched version.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Step 1: Check installed kernel version with `uname -r` and compare against 6.12.0-6.12.2
Step 2: Verify s390/PCI subsystem is in use by checking `grep -i pci /proc/cpuinfo` or `lspci | grep -i ibm` on supported systems
Step 3: Monitor kernel logs with `dmesg | grep -i 'zpci\|hotplug' | tail -50` for double removal attempts or hotplug warnings
Step 4: After patching, confirm kernel version with `uname -r` shows 6.12.2 or later, then reboot and verify with `uname -r` again

FAQ

What is CVE-2024-56699?

This is a logic error in the Linux kernel's s390 PCI hotplug handler where the removal of hotplug slots could be executed twice, leading to potential kernel panics or memory corruption on IBM System z platforms.

Is CVE-2024-56699 being actively exploited?

No, CVE-2024-56699 is not listed as actively exploited by CISA, and no public exploits are currently available. However, it is a high-severity vulnerability that should be patched promptly on affected systems.

What versions of Kernel are affected by CVE-2024-56699?

Linux kernel versions 6.12.0 through 6.12.2 are vulnerable. Version 6.12.2 contains the fix, so users should upgrade to 6.12.2 or any later stable kernel release.

How do I check if my server is vulnerable to CVE-2024-56699?

Run `uname -r` to display your kernel version. If it shows 6.12.0, 6.12.1, or 6.12.2, your system is vulnerable and requires an immediate kernel update.

Does Defensia detect CVE-2024-56699?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-56699 will appear in your dashboard with remediation steps.

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References

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