CVE-2022-49769: gfs2: Check sb_bsize_shift after reading superblock
Vulnerability summary
CVE-2022-49769 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.3% 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 7 · Related 7Timeline
- 01-05-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: gfs2: Check sb_bsize_shift after reading superblock Fuzzers like to scribble over sb_bsize_shift but in reality it's very unlikely that this field would be corrupted on its own. Nevertheless it should be checked to avoid the possibility of messy mount errors due to bad calculations. It's always a fixed value based on the block size so we can just check that it's the expected value. Tested with: mkfs.gfs2 -O -p lock_nolock /dev/vdb for i in 0 -1 64 65 32 33; do gfs2_edit -p sb field sb_bsize_shift $i /dev/vdb mount /dev/vdb /mnt/test && umount /mnt/test done Before this patch we get a withdraw after [ 76.413681] gfs2: fsid=loop0.0: fatal: invalid metadata block [ 76.413681] bh = 19 (type: exp=5, found=4) [ 76.413681] function = gfs2_meta_buffer, file = fs/gfs2/meta_io.c, line = 492 and with UBSAN configured we also get complaints like [ 76.373395] UBSAN: shift-out-of-bounds in fs/gfs2/ops_fstype.c:295:19 [ 76.373815] shift exponent 4294967287 is too large for 64-bit type 'long unsigned int' After the patch, these complaints don't appear, mount fails immediately and we get an explanation in dmesg.
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
0.22%
Chance of exploitation in the next 30 days
Percentile
12%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.22% 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.
Ubuntu114 products
- linuxAll versions (No fix recorded) | < 4.15.0-206.217 | < 5.4.0-144.161 | < 5.15.0-67.74
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1151.164 | < 5.4.0-1097.105 | < 5.15.0-1031.35
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < d6b1e8ea6f3418c3b461ad5a35cdc93c996b2c87 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 1ad197097343568066a8ffaa27ee7d0ae6d9f476 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 15c83fa0fd659dd9fbdc940a560b61236e876a80 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 8b6534c9ae9dba5489703a19d8ba6c8f2cfa33c2 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 5fa30be7ba81191b0a0c7239a89befc0c94286d5 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 28275a7c84d21c55ab3282d897f284d8d527173c | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 16670534c7cff1acd918a6a5ec751b14e7436b76 | ≥ b3b94faa5fe5968827ba0640ee9fba4b3e7f736e, < 670f8ce56dd0632dc29a0322e188cc73ce3c6b92 | 2.6.19
- linux_kernel< 4.9.334 | ≥ 4.10, < 4.14.300 | ≥ 4.15, < 4.19.267 | ≥ 4.20, < 5.4.225 | ≥ 5.5, < 5.10.156 | ≥ 5.11, < 5.15.80 | ≥ 5.16, < 6.0.10
Debian1 product
- linux< 6.0.10-1
3 vendors · 117 products
