CVE-2022-49699: filemap: Handle sibling entries in filemap_get_read_batch()

Severity: medium (CVSS 5.5 v3.1)
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: 2025-02-26 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: filemap: Handle sibling entries in filemap_get_read_batch() If a read races with an invalidation followed by another read, it is possible for a folio to be replaced with a higher-order folio. If that happens, we'll see a sibling entry for the new folio in the next iteration of the loop. This manifests as a NULL pointer dereference while holding the RCU read lock. Handle this by simply returning. The next call will find the new folio and handle it correctly. The other ways of handling this rare race are more complex and it's just not worth it.

Affected products

Linux kernel: from 5.12 before 5.18.8; 5.19-rc1, 5.19-rc2, 5.19-rc3 — fixed in 5.18.8

How to fix

Upgrade to a fixed version: Linux kernel 5.18.8. Check the vendor advisory for mitigations.

References

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