Linux Kernel up to 7.1.4 cxl/test lib/string_helpers.c setup_xor_mapping buffer overflow

Summaryinfo

A vulnerability has been found in Linux Kernel up to 7.1.4 and classified as very critical. The affected element is the function setup_xor_mapping of the file lib/string_helpers.c of the component cxl/test. Performing a manipulation results in buffer overflow. This vulnerability is reported as CVE-2026-80639. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.1.4. This affects the function setup_xor_mapping of the file lib/string_helpers.c of the component cxl/test. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: cxl/test: Fix __fortify_panic Fix a runtime assertion in setup_xor_mapping(). Fortify complains that it is potentially overflowing the xormaps array per __counted_by(nr_maps). Quiet the false positive by initializing @nr_maps earlier. memcpy: detected buffer overflow: 32 byte write of buffer size 0 WARNING: lib/string_helpers.c:1036 at __fortify_report+0x4d/0xa0, CPU#8: modprobe/2728 Call Trace: __fortify_panic+0xd/0xf setup_xor_mapping+0x6c/0xa0 [cxl_translate] [ dj: Fixed up @nr_entries to @nr_maps in commit log. ]

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-80639 since 08/26/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/28/2026).

Upgrading to version 7.1.5 eliminates this vulnerability. Applying the patch 8c4f27a7f364eab514d2fa55c11f39d505122f1b/08326b92c7a414a73b5b308d1daf0e91e0134dfc is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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