Linux Kernel up to 7.2.5 btrfs privileges management

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been rated as problematic. Impacted is an unknown function of the component btrfs. The manipulation leads to privileges management. This vulnerability is listed as CVE-2026-90263. The attack must be carried out locally. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been rated as problematic. This issue affects an unknown function of the component btrfs. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is integrity. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: btrfs: check if root is readonly when setting posix acl For a filesystem which has btrfs read-only property set to true, all write operations including acl and xattr should be denied. However, acl can still be set even if btrfs ro property is true. This happens because no function on the set_acl code path checks the root is readonly or not. It was checked in btrfs_setxattr_trans() but got removed in commit 353c2ea735e4 ("btrfs: remove redundant readonly root check in btrfs_setxattr_trans") That commit didn't check if all the callers properly check the root's read-only flag. A previous fix is commit b51111271b03 ("btrfs: check if root is readonly while setting security xattr"). Always check if the root is read-only before performing the set acl operation.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-90263 since 09/11/2026. The exploitation is known to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch d5602f96ff1e266f069b4d0d94f441050e057e06/01c2f41fc441f75b3f9326443372faceb1cb6638 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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