CVE-2024-35880: io_uring/kbuf: hold io_buffer_list reference over mmap

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-19 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: hold io_buffer_list reference over mmap If we look up the kbuf, ensure that it doesn't get unregistered until after we're done with it. Since we're inside mmap, we cannot safely use the io_uring lock. Rely on the fact that we can lookup the buffer list under RCU now and grab a reference to it, preventing it from being unregistered until we're done with it. The lookup returns the io_buffer_list directly with it referenced.

Affected products

Linux kernel: from 6.6.5 before 6.6.26; from 6.7.1 before 6.8.5; 6.7, 6.7-rc4, 6.7-rc5, 6.7-rc6, 6.7-rc7, 6.7-rc8 (+2) — fixed in 6.6.26, 6.8.5

How to fix

Upgrade to a fixed version: Linux kernel 6.6.26, 6.8.5. Check the vendor advisory for mitigations.

References

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