CVE-2022-49171

What it is

In the Linux kernel, the following vulnerability has been resolved: ext4: don't BUG if someone dirty pages without asking ext4 first [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/[email protected] [2] https://lore.kernel.org/r/[email protected]

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-02-26 07:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-05 20:16 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-02-26 07:00 UTC

Last modified

2026-11-05 20:16 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-617

Record status

Analyzed

Affected

• Linux Kernel < 4.9.311
• Linux Kernel < 4.14.276
• Linux Kernel < 4.19.238
• Linux Kernel < 5.4.189
• Linux Kernel < 5.10.110
• Linux Kernel < 5.15.33
• Linux Kernel < 5.16.19
• Linux Kernel < 5.17.2

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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