CVE-2026-64219drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async

Official description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async [Why&How] dc_process_dmub_aux_transfer_async() copies payload->length bytes into a 16-byte stack buffer (dpaux.data[16]) guarded only by an ASSERT(), which is a no-op in release builds. If a caller ever passes length > 16 this results in a stack buffer overflow via memcpy. Additionally, link_index is used to dereference dc->links[] without bounds checking against dc->link_count, risking an out-of-bounds access. Replace the ASSERT with a hard runtime check that returns false when payload->length exceeds the destination buffer size, and add a bounds check for link_index before it is used. (cherry picked from commit ba4caa9fecdf7a38f98c878ad05a8a64148b6881)

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/d6590e3f766e3111dd1beaf88b9384d117acfa6b
• https://git.kernel.org/stable/c/16a5fa57565afb6bf37e18129921c270c93d8e2b
• https://git.kernel.org/stable/c/90c398e822ca76e40548df0c061dd4f93ea92d71
• https://git.kernel.org/stable/c/3265f3ed373fb8048be713aadcdf702579a0e53d
• https://git.kernel.org/stable/c/1ecde19bfce6535bffddad1139ff466b6d401b8e
• https://git.kernel.org/stable/c/1c8c6e912f2945b2a3e669afca6b52174b88e86e
• https://git.kernel.org/stable/c/6c92f6d9600efa3ef0d9e560a2b52776d9803c29