Linux kernel: DIV0 in DRM AMD display get_estimated_bw()
CVE-2026-90035 Published on September 16, 2026
drm/amd/display: fix division by zero in get_estimated_bw()
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: fix division by zero in get_estimated_bw()
get_estimated_bw() divides by link->dpia_bw_alloc_config.bw_granularity,
which is zeroed by reset_bw_alloc_struct() and only populated once
DP_TUNNELING_BW_ALLOC_CAP_CHANGED has been handled.
link_dp_dpia_handle_bw_alloc_status(), the DPCD interrupt handler,
calls get_estimated_bw() whenever DP_TUNNELING_ESTIMATED_BW_CHANGED
is set, independently of whether DP_TUNNELING_BW_ALLOC_CAP_CHANGED
has ever fired for that link. A connected USB4/DPIA tunneling device
that reports an estimated-bandwidth change before ever reporting a
capability change drives a division by zero in this IRQ path.
link_dpia_send_bw_alloc_request() already guards the same
bw_granularity division; add the identical guard here rather than
introducing a new pattern.
(cherry picked from commit f2a961457c33dc34223aad5c9e8971de34a4eed3)
Products Associated with CVE-2026-90035
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Affected Versions
Linux:- Version 8e5cfe547bf3beeb29d9608be68d22dff2b5012b and below 4c5b61b9df6ab33b55f228e1b6579cefad11a9f7 is affected.
- Version 8e5cfe547bf3beeb29d9608be68d22dff2b5012b and below ac2ab58a79bf2401ae8c5d1c030bf0a5a376f43a is affected.
- Version 8e5cfe547bf3beeb29d9608be68d22dff2b5012b and below 4814f28c45f58a71a80d09b80a60da6a063b539a is affected.
- Version 8e5cfe547bf3beeb29d9608be68d22dff2b5012b and below b08c3d5ee7feadd821208f7c2c1ec02a16ce5878 is affected.
- Version 8e5cfe547bf3beeb29d9608be68d22dff2b5012b and below f63de9054da858d57054474c32464106f8375e0d is affected.
- Version 6.3 is affected.
- Before 6.3 is unaffected.
- Version 6.6.157, <= 6.6.* is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.51, <= 6.18.* is unaffected.
- Version 7.2.5, <= 7.2.* is unaffected.
- Version 7.3-rc2, <= * is unaffected.