Linux Kernel up to 6.17.2 PCI aer_ratelimit null pointer dereference

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.17.2. This affects the function aer_ratelimit of the component PCI. The manipulation results in null pointer dereference. This vulnerability was named CVE-2025-40034. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.17.2. Affected is the function aer_ratelimit of the component PCI. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: PCI/AER: Avoid NULL pointer dereference in aer_ratelimit() When platform firmware supplies error information to the OS, e.g., via the ACPI APEI GHES mechanism, it may identify an error source device that doesn't advertise an AER Capability and therefore dev->aer_info, which contains AER stats and ratelimiting data, is NULL. pci_dev_aer_stats_incr() already checks dev->aer_info for NULL, but aer_ratelimit() did not, leading to NULL pointer dereferences like this one from the URL below: {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 0 {1}[Hardware Error]: event severity: corrected {1}[Hardware Error]: device_id: 0000:00:00.0 {1}[Hardware Error]: vendor_id: 0x8086, device_id: 0x2020 {1}[Hardware Error]: aer_cor_status: 0x00001000, aer_cor_mask: 0x00002000 BUG: kernel NULL pointer dereference, address: 0000000000000264 RIP: 0010:___ratelimit+0xc/0x1b0 pci_print_aer+0x141/0x360 aer_recover_work_func+0xb5/0x130 [8086:2020] is an Intel "Sky Lake-E DMI3 Registers" device that claims to be a Root Port but does not advertise an AER Capability. Add a NULL check in aer_ratelimit() to avoid the NULL pointer dereference. Note that this also prevents ratelimiting these events from GHES. [bhelgaas: add crash details to commit log]

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2025-40034 since 04/16/2025. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 271871 (Linux Distros Unpatched Vulnerability : CVE-2025-40034), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch 41683624cbff0a26bb7e0627f4a7e1b51a8779a8/deb2f228388ff3a9d0623e3b59a053e9235c341d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (271871) and CERT Bund (WID-SEC-2025-2431). Once again VulDB remains the best source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• Microsoft Azure
• Dell NetWorker
• Dell ECS

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.17.0
• 6.17.1
• 6.17.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Once again VulDB remains the best source for vulnerability data.

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