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CVE-2026-23238

Updated on 04 Mar 2026

Severity

5.5 Medium severity

Details

CVSS score
5.5
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE ID
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

romfs: check sb_set_blocksize() return value

romfs_fill_super() ignores the return value of sb_set_blocksize(), which can fail if the requested block size is incompatible with the block device’s configuration.

This can be triggered by setting a loop device’s block size larger than PAGE_SIZE using ioctl(LOOP_SET_BLOCK_SIZE, 32768), then mounting a romfs filesystem on that device.

When sb_set_blocksize(sb, ROMBSIZE) is called with ROMBSIZE=4096 but the device has logical_block_size=32768, bdev_validate_blocksize() fails because the requested size is smaller than the device’s logical block size. sb_set_blocksize() returns 0 (failure), but romfs ignores this and continues mounting.

The superblock’s block size remains at the device’s logical block size (32768). Later, when sb_bread() attempts I/O with this oversized block size, it triggers a kernel BUG in folio_set_bh():

kernel BUG at fs/buffer.c:1582! BUG_ON(size > PAGE_SIZE);

Fix by checking the return value of sb_set_blocksize() and failing the mount with -EINVAL if it returns 0.

Details

Affected product:
AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
Affected packages:
linux @ 4.19.0 (+18 more)

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Amazon Linux 2023 Will Not Fix
47 kernels
  • 6.1.79-99.164.amzn2023
  • 6.1.84-99.169.amzn2023
  • 6.1.82-99.168.amzn2023
  • 6.1.90-99.173.amzn2023
  • 6.1.87-99.174.amzn2023
  • 6.1.91-99.172.amzn2023
  • 6.1.97-104.177.amzn2023
  • 6.1.94-99.176.amzn2023
  • 6.1.102-108.177.amzn2023
  • 6.1.106-116.188.amzn2023
  • 6.1.102-111.182.amzn2023
  • 6.1.79-99.167.amzn2023
  • 6.1.92-99.174.amzn2023
  • 6.1.96-102.177.amzn2023
  • 6.1.109-118.189.amzn2023
  • 6.1.112-122.189.amzn2023
  • 6.1.111-120.187.amzn2023
  • 6.1.115-126.197.amzn2023
  • 6.1.119-129.201.amzn2023
  • 6.1.124-134.200.amzn2023
  • 6.1.127-135.201.amzn2023
  • 6.1.128-136.201.amzn2023
  • 6.1.129-138.220.amzn2023
  • 6.1.130-139.222.amzn2023
  • 6.1.131-143.221.amzn2023
  • 6.1.132-147.221.amzn2023
  • 6.1.134-150.224.amzn2023
  • 6.1.112-124.190.amzn2023
  • 6.1.140-154.222.amzn2023
  • 6.1.141-155.222.amzn2023
  • 6.1.134-152.225.amzn2023
  • 6.1.144-170.251.amzn2023
  • 6.1.147-172.266.amzn2023
  • 6.1.148-173.267.amzn2023
  • 6.1.150-174.273.amzn2023
  • 6.1.141-165.249.amzn2023
  • 6.1.141-167.250.amzn2023
  • 6.1.147-172.259.amzn2023
  • 6.1.153-175.280.amzn2023
  • 6.1.155-176.282.amzn2023
  • 6.1.156-177.286.amzn2023
  • 6.1.158-178.288.amzn2023
  • 6.1.159-181.297.amzn2023
  • 6.1.163-186.299.amzn2023
  • 6.1.158-180.294.amzn2023
  • 6.1.159-182.297.amzn2023
  • 6.1.161-183.298.amzn2023
Debian 11 Released
37 kernels
  • 5.10.46-5
  • 5.10.70-1
  • 5.10.46-4
  • 5.10.84-1
  • 5.10.92-1
  • 5.10.92-2
  • 5.10.103-1
  • 5.10.106-1
  • 5.10.113-1
  • 5.10.120-1
  • 5.10.127-1
  • 5.10.127-2
  • 5.10.136-1
  • 5.10.140-1
  • 5.10.149-1
  • 5.10.149-2
  • 5.10.158-2
  • 5.10.162-1
  • 5.10.179-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.178-3
  • 5.10.205-2
  • 5.10.205-1
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 11 cloud Released
17 kernels
  • 5.10.113-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.205-2
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 12 Released
34 kernels
  • 6.1.38-1
  • 6.1.38-2
  • 6.1.38-4
  • 6.1.52-1
  • 6.1.55-1
  • 6.1.64-1
  • 6.1.66-1
  • 6.1.69-1
  • 6.1.76-1
  • 6.1.27-1
  • 6.1.67-1
  • 6.1.85-1
  • 6.1.90-1
  • 6.1.94-1
  • 6.1.99-1
  • 6.1.106-3
  • 6.1.112-1
  • 6.1.115-1
  • 6.1.119-1
  • 6.1.123-1
  • 6.1.128-1
  • 6.1.124-1
  • 6.1.129-1
  • 6.1.133-1
  • 6.1.135-1
  • 6.1.137-1
  • 6.1.140-1
  • 6.1.139-1
  • 6.1.147-1
  • 6.1.148-1
  • 6.1.153-1
  • 6.1.158-1
  • 6.1.159-1
  • 6.1.162-1
Debian 13 Released
3 kernels
  • 6.12.73-1
  • 6.12.63-1
  • 6.12.69-1
Ubuntu 22.04 Planned —
Ubuntu 24.04 Released
45 kernels
  • 6.8.0-35.35
  • 6.8.0-38.38
  • 6.8.0-36.36
  • 6.8.0-39.39
  • 6.8.0-40.40
  • 6.8.0-41.41
  • 6.8.0-44.44
  • 6.8.0-45.45
  • 6.8.0-31.31
  • 6.8.0-47.47
  • 6.8.0-48.48
  • 6.8.0-49.49
  • 6.8.0-50.51
  • 6.8.0-51.52
  • 6.8.0-52.53
  • 6.8.0-54.56
  • 6.8.0-55.57
  • 6.8.0-53.55
  • 6.8.0-56.58
  • 6.8.0-57.59
  • 6.8.0-58.60
  • 6.8.0-59.61
  • 6.8.0-60.63
  • 6.8.0-62.65
  • 6.8.0-63.66
  • 6.8.0-64.67
  • 6.8.0-71.71
  • 6.8.0-78.78
  • 6.8.0-79.79
  • 6.8.0-84.84
  • 6.8.0-85.85
  • 6.8.0-83.83
  • 6.8.0-86.87
  • 6.8.0-87.88
  • 6.8.0-88.89
  • 6.8.0-90.91
  • 6.8.0-94.96
  • 6.8.0-100.100
  • 6.8.0-101.101
  • 6.8.0-106.106
  • 6.8.0-107.107
  • 6.8.0-110.110
  • 6.8.0-111.111
  • 6.8.0-117.117
  • 6.8.0-124.124
Ubuntu 24.04 AWS Planned —