CVE-2026-43366: io_uring/kbuf: check if target buffer list is still legacy on recycle

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-10-19
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: check if target buffer list is still legacy on recycle There's a gap between when the buffer was grabbed and when it potentially gets recycled, where if the list is empty, someone could've upgraded it to a ring provided type. This can happen if the request is forced via io-wq. The legacy recycling is missing checking if the buffer_list still exists, and if it's of the correct type. Add those checks.

Affected products

Linux kernel: from 5.19 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.78; from 6.13 before 6.18.19; from 6.19 before 6.19.9; 7.0-rc1, 7.0-rc2, 7.0-rc3 — fixed in 6.1.167, 6.12.78, 6.18.19, 6.19.9, 6.6.130

How to fix

Upgrade to a fixed version: Linux kernel 6.1.167, 6.12.78, 6.18.19, 6.19.9. Check the vendor advisory for mitigations.

References

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