CVE-2022-49171
MediumIn 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]
CVSS 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness type
CWE-617CVE-2022-49171 is classified as CWE-617
See CWE-617 on MITRE CWE for full details on this weakness type.
Affected versions
Linux kernel versions
2.6.37
and later are affected. Fixed in
4.9.311,
4.14.276,
4.19.238,
5.4.189,
5.10.110,
5.15.33,
5.16.19,
5.17.2,
5.18
and their respective stable series.
References
The following references provide additional information about CVE-2022-49171 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/0d3a6926f7e8be3c897fa46216ce13b119a9f56a
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PatchKernel patch commithttps://git.kernel.org/stable/c/330d0e44fc5a47c27df958ecdd4693a3cb1d8b81
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PatchKernel patch commithttps://git.kernel.org/stable/c/343117559ef41e992e326f7a92da1a8f254dfa8c
Frequently asked questions
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What is CVE-2022-49171?
CVE-2022-49171 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 2.6.37 onward and has been patched in 4.9.311, 4.14.276, 4.19.238 and others. CVE-2022-49171 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2022-49171?
CVE-2022-49171 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2022-49171?
Yes — CVE-2022-49171 has been patched. Fixed versions include 4.9.311, 4.14.276, 4.19.238 and others. If you are running Linux kernel 2.6.37 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2022-49171 actively exploited?
No — CVE-2022-49171 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.