CVE-2026-80656

What it is

In the Linux kernel, the following vulnerability has been resolved: hfsplus: Add a sanity check for btree node size Syzbot reported an uninit-value bug in [1] with a corrupted HFS+ image, during the file system mounting process, specifically while loading the catalog, a corrupted node_size value of 1 caused the rec_off argument passed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively large. Consequently, the function failed to return a valid value to initialize the off variable, triggering the bug [1]. Every node starts from BTree node descriptor: struct hfs_bnode_desc. So, the size of node cannot be lesser than that. However, technical specification declares that: "The node size (which is expressed in bytes) must be power of two, from 512 through 32,768, inclusive." Add a check for btree node size base on technical specification. [1] BUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584 hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584 hfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382 hfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553 get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694 get_tree_bdev+0x38/0x50 fs/super.c:1717 hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709 vfs_get_tree+0xb3/0x5d0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline]

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-08-28 08:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-29 07:16 UTC Last updatedMost recent change to the record

Details

Published

2026-08-28 08:16 UTC

Last modified

2026-08-29 07:16 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Received

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High