Linux Kernel up to 6.18.13/6.19.3 arch_set_shadow_stack_status stack-based overflow

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.18.13/6.19.3. This vulnerability affects the function arch_set_shadow_stack_status. This manipulation causes stack-based overflow. This vulnerability is tracked as CVE-2026-45876. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.13/6.19.3. It has been declared as critical. Affected by this vulnerability is the function arch_set_shadow_stack_status. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: arm64/gcs: Fix error handling in arch_set_shadow_stack_status() alloc_gcs() returns an error-encoded pointer on failure, which comes from do_mmap(), not NULL. The current NULL check fails to detect errors, which could lead to using an invalid GCS address. Use IS_ERR_VALUE() to properly detect errors, consistent with the check in gcs_alloc_thread_stack().

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-45876 since 05/13/2026. The exploitation appears to be easy. 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 06/26/2026).

Upgrading to version 6.18.14 or 6.19.4 eliminates this vulnerability. Applying the patch c787a235deb33be6eda40beee8f561da5fd8cb8c/a4741114c9622346c4bbb8cc2bbd88153616ffaf/53c998527ffa60f9deda8974a11ad39790684159 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 vulnerability database at CERT Bund (WID-SEC-2026-1700). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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