CVE-2024-56616: drm/dp_mst: Fix MST sideband message body length check

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-12-27 · updated 2026-06-17
Weakness: CWE-129

Description

In the Linux kernel, the following vulnerability has been resolved: drm/dp_mst: Fix MST sideband message body length check Fix the MST sideband message body length check, which must be at least 1 byte accounting for the message body CRC (aka message data CRC) at the end of the message. This fixes a case where an MST branch device returns a header with a correct header CRC (indicating a correctly received body length), with the body length being incorrectly set to 0. This will later lead to a memory corruption in drm_dp_sideband_append_payload() and the following errors in dmesg: UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25 index -1 is out of range for type 'u8 [48]' Call Trace: drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] memcpy: detected field-spanning write (size 18446744073709551615) of single field "&msg->msg[msg->curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256) Call Trace: drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper]

Affected products

Linux kernel: before 5.10.233; from 5.11 before 5.15.176; from 5.16 before 6.1.120; from 6.2 before 6.6.66; from 6.7 before 6.12.5; 6.13-rc1 — fixed in 5.10.233, 5.15.176, 6.1.120, 6.12.5, 6.6.66

How to fix

Upgrade to a fixed version: Linux kernel 5.10.233, 5.15.176, 6.1.120, 6.12.5. Check the vendor advisory for mitigations.

References

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