CVE-2026-89818: drm/amdgpu/vcn: fix integer overflow in dec_msg buffer count check

Severity: high (CVSS 7.1 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: 2026-09-16 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: fix integer overflow in dec_msg buffer count check If the supplied msg[2] (num_buffers) is 0x3FFFFFFF, the expression 6 + num_buffers * 4 wraps to 2 and the bounds check passes, letting the parser loop far past the end of the message BO. Triggering it additionally requires a ~4GiB mapping so that msg[1] survives the earlier "header does not fit in BO" check. Rewrite the test in division form, which is overflow-free by construction. Also update the message to reflect that msg is invalid.

Affected products

Linux kernel: from 6.1.175 before 6.1.188; from 6.6.140 before 6.6.157; from 6.12.90 before 6.12.110; from 6.18.32 before 6.18.51; from 5.15.209 before 5.16; from 7.0.9 before 7.1 — fixed in 5.16, 6.1.188, 6.12.110, 6.18.51, 6.6.157, 7.1

How to fix

Upgrade to a fixed version: Linux kernel 5.16, 6.1.188, 6.12.110, 6.18.51. Check the vendor advisory for mitigations.

References

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