CVE-2025-38172: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: erofs: avoid using multiple devices with different type For multiple devices, both primary and extra devices should be the same type. `erofs_init_device` has already guaranteed that if the primary is a file-backed device, extra devices should also be regular files. However, if the primary is a block device while the extra device is a file-backed device, `erofs_init_device` will get an ENOTBLK, which is not treated as an error in `erofs_fc_get_tree`, and that leads to an UAF: erofs_fc_get_tree get_tree_bdev_flags(erofs_fc_fill_super) erofs_read_superblock erofs_init_device // sbi->dif0 is not inited yet, // return -ENOTBLK deactivate_locked_super free(sbi) if (err is -ENOTBLK) sbi->dif0.file = filp_open() // sbi UAF So if -ENOTBLK is hitted in `erofs_init_device`, it means the primary device must be a block device, and the extra device is not a block device. The error can be converted to -EINVAL.

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CVSS v3.1 Score

7.8

HIGH

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

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.12 — 6.12.34
linux	linux_kernel	6.13 — 6.15.3

References

Advisories & Patches

https://git.kernel.org/stable/c/65115472f741ca000d7ea4a5922214f93cd1516e https://git.kernel.org/stable/c/9748f2f54f66743ac77275c34886a9f890e18409 https://git.kernel.org/stable/c/cd04beb9ce2773a16057248bb4fa424068ae3807

Frequently Asked Questions

What is CVE-2025-38172? +

In the Linux kernel, the following vulnerability has been resolved: erofs: avoid using multiple devices with different type For multiple devices, both primary and extra devices should be the same type. `erofs_init_device` has already guaranteed that if the primary is a file-backed device, extra devices should also be regular files. However, if the primary is a block device while the extra device is a file-backed device, `erofs_init_device` will get an ENOTBLK, which is not treated as an error in `erofs_fc_get_tree`, and that leads to an UAF: erofs_fc_get_tree get_tree_bdev_flags(erofs_fc_fill_super) erofs_read_superblock erofs_init_device // sbi->dif0 is not inited yet, // return -ENOTBLK deactivate_locked_super free(sbi) if (err is -ENOTBLK) sbi->dif0.file = filp_open() // sbi UAF So if -ENOTBLK is hitted in `erofs_init_device`, it means the primary device must be a block device, and the extra device is not a block device. The error can be converted to -EINVAL. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-38172? +

CVE-2025-38172 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38172? +

CVE-2025-38172 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38172? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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