What’s Vulnerable › Vulnerabilities

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

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-11 · updated 2026-10-19

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.

Affected products

• Linux kernel: from 6.1.178 before 6.1.188; 6.5 — fixed in 6.1.188, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 6.1.188, 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0dbc2e94b81df5a1264068b6ed3605c654b8afcb
• 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/97d71ebee48cd1b29091762b3e5cca4f815dd84c
• https://git.kernel.org/stable/c/b2326338dc683e8c1067c0cbf7a47986c4190902

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