Executive brief
A vulnerability was identified in the Linux kernel's ext4 filesystem driver where certain internal resources were not properly released during file operations. This flaw can lead to a resource leak, potentially impacting system stability or performance over time as the system fails to reclaim memory. This issue primarily affects systems using the ext4 filesystem when specific extended attribute configurations are in use.
Technical details
A reference count leak exists in the ext4 filesystem component of the Linux kernel. Specifically, the function `ext4_xattr_inode_dec_ref_all()` calls `ext4_get_inode_loc()` to retrieve a buffer head (`iloc.bh`) but fails to invoke `brelse()` to release it when `block_csum` is false. This flaw was introduced by a previous commit intended to ignore extended attributes past the end of a block. An attacker with local access could potentially trigger this leak repeatedly to exhaust kernel memory. Patches have been released across multiple stable kernel branches to ensure `brelse()` is properly called.
Affected products
- Linux Linux Kernel ext4 filesystem driver
Timeline
- 2026-04-06: other: Patch authored by Sohei Koyama
- 2026-05-27: advisory: CVE-2026-46046 published by kernel.org and NVD
References
- https://git.kernel.org/stable/c/097227f1ffe1a85bc3c359f81c71e3d40e06e920
- https://git.kernel.org/stable/c/1bc1107a3a403a6d440673ed6666f7b07ef868a8
- https://git.kernel.org/stable/c/1e6b0a69bf2c9c819255c7566e4355536d81d9cf
- https://git.kernel.org/stable/c/77d059519382bd66283e6a4e83ee186e87e7708f
- https://git.kernel.org/stable/c/f072906688933bf47fabbaf63560be03357c8298