CVE-2022-49769: In the Linux kernel, the following vulnerability has been resolved: gfs2: Check sb_bsize_shift after reading superblock Fuzzers like to scribble ove...

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.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.18%

7.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 4.9.334
Linux	Linux Kernel	>= 4.10, < 4.14.300
Linux	Linux Kernel	>= 4.15, < 4.19.267
Linux	Linux Kernel	>= 4.20, < 5.4.225
Linux	Linux Kernel	>= 5.5, < 5.10.156
Linux	Linux Kernel	>= 5.11, < 5.15.80
Linux	Linux Kernel	>= 5.16, < 6.0.10

References

Timeline

Published: May 1, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2022-49769?

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.

How severe is CVE-2022-49769?

CVE-2022-49769 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2022-49769?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.