CVE-2022-49171: ext4: don't BUG if someone dirty pages without asking ext4 first
Vulnerability summary
CVE-2022-49171 is a medium (CVSS 5.5) Reachable Assertion vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 20% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 26-02-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
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/20180103100430.GE4911@quack2.suse.cz [2] https://lore.kernel.org/r/Yg0m6IjcNmfaSokM@google.com
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
20%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.28% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu107 products
- linuxAll versions (No fix recorded) | < 4.15.0-189.200 | < 5.4.0-117.132 | < 5.15.0-37.39
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1137.148 | < 5.4.0-1078.84 | < 5.15.0-1011.14
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 5db60e76edf5680ff1f3a7221036fc44b308f146 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < d666dfaa571465a19f014534a214c255ea33f301 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 0d3a6926f7e8be3c897fa46216ce13b119a9f56a | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 5a016c053f426a73752c3b41b60b497b58694d48 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 330d0e44fc5a47c27df958ecdd4693a3cb1d8b81 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < a0856764dc1276ad2dc7891288c2e9246bf11a37 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 343117559ef41e992e326f7a92da1a8f254dfa8c | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < 677c9d30e8487bee6c8e3b034070319d98f6e203 | ≥ a42afc5f56f319107e987aa6adf2f65d93d527c7, < cc5095747edfb054ca2068d01af20be3fcc3634f | 2.6.37
- linux_kernel< 4.9.311 | ≥ 4.10, < 4.14.276 | ≥ 4.15, < 4.19.238 | ≥ 4.20, < 5.4.189 | ≥ 5.5, < 5.10.110 | ≥ 5.11, < 5.15.33 | ≥ 5.16, < 5.16.19 | ≥ 5.17, < 5.17.2
Debian1 product
- linux< 5.17.3-1
3 vendors · 110 products
