Bug 2492768 (CVE-2026-53136)

Summary: CVE-2026-53136 kernel: drm/amd/display: Clamp VBIOS HDMI retimer register count to array size
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's AMD display driver. This vulnerability occurs when the driver processes malformed VBIOS (Video Basic Input/Output System) data. Specifically, unvalidated register counts in the VBIOS can lead to an out-of-bounds memory write during the driver's initialization. This memory corruption could allow an attacker with local access to potentially cause a system crash (denial of service) or execute arbitrary code.
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Description OSIDB Bzimport 2026-06-25 10:04:43 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Clamp VBIOS HDMI retimer register count to array size

[Why & How]
The VBIOS integrated info tables (v1_11 and v2_1) contain HdmiRegNum and
Hdmi6GRegNum fields that are used as loop bounds when copying retimer I2C
register settings into fixed-size arrays (dp*_ext_hdmi_reg_settings[9]
and dp*_ext_hdmi_6g_reg_settings[3]). These u8 fields are not validated
before use, so a malformed VBIOS can specify values up to 255, causing an
out-of-bounds heap write during driver probe.

Clamp each register count to the destination array size using min_t()
before the copy loops, in both get_integrated_info_v11() and
get_integrated_info_v2_1().

(cherry picked from commit 5a7f0ef90195940c54b0f5bb85b87da55f038c69)
Comment 1 Keith Grant 2026-06-25 23:40:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062543-CVE-2026-53136-b8ab@gregkh/T