CVE-2021-47114: ocfs2: fix data corruption by fallocate
Vulnerability summary
CVE-2021-47114 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.3% 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 6 · Related 6Timeline
- 15-03-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size. Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily. qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ -O qcow2 -o compat=1.1 $qcow_image.conv The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size. fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0 fallocate(11, 0, 2276196352, 65536) = 0 v1: https://www.spinics.net/lists/linux-fsdevel/msg193999.html v2: https://lore.kernel.org/linux-fsdevel/20210525093034.GB4112@quack2.suse.cz/T/
CVSS metrics
5 scores · 4 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
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.23%
Chance of exploitation in the next 30 days
Percentile
13%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.23% 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 causeNo weakness data has been published for this record.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu87 products
- linuxAll versions (No fix recorded) | < 4.15.0-154.161 | < 5.4.0-81.91
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1110.117 | < 5.4.0-1055.58
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < 624fa7baa3788dc9e57840ba5b94bc22b03cda57 | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < 33e03adafb29eedae1bae9cdb50c1385279fcf65 | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < a1700479524bb9cb5e8ae720236a6fabd003acae | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < cec4e857ffaa8c447f51cd8ab4e72350077b6770 | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < cc2edb99ea606a45182b5ea38cc8f4e583aa0774 | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < c8d5faee46242c3f33b8a71a4d7d52214785bfcc | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < 0a31dd6fd2f4e7db538fb6eb1f06973d81f8dd3b | ≥ 385820a38d5e7c70b20af4d68767b1920b1e4133, < 6bba4471f0cc1296fe3c2089b9e52442d3074b2e | 2.6.23
- linux_kernel< 4.4.272 | ≥ 4.5, < 4.9.272 | ≥ 4.10, < 4.14.236 | ≥ 4.15, < 4.19.194 | ≥ 4.20, < 5.4.125 | ≥ 5.5, < 5.10.43 | ≥ 5.11, < 5.12.10 | 5.13:rc1 | 5.13:rc2 | 5.13:rc3 | 5.13:rc4
Debian1 product
- linux< 5.10.46-1
3 vendors · 90 products
