CVE-2026-45960: hfsplus: return error when node already exists in hfs_bnode_create

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: hfsplus: return error when node already exists in hfs_bnode_create When hfs_bnode_create() finds that a node is already hashed (which should not happen in normal operation), it currently returns the existing node without incrementing its reference count. This causes a reference count inconsistency that leads to a kernel panic when the node is later freed in hfs_bnode_put(): kernel BUG at fs/hfsplus/bnode.c:676! BUG_ON(!atomic_read(&node->refcnt)) This scenario can occur when hfs_bmap_alloc() attempts to allocate a node that is already in use (e.g., when node 0's bitmap bit is incorrectly unset), or due to filesystem corruption. Returning an existing node from a create path is not normal operation. Fix this by returning ERR_PTR(-EEXIST) instead of the node when it's already hashed. This properly signals the error condition to callers, which already check for IS_ERR() return values.

Affected products

Linux kernel: from 2.6.16.1 before 5.10.252; from 5.11 before 5.15.202; from 5.16 before 6.1.165; from 6.2 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14 — fixed in 5.10.252, 5.15.202, 6.1.165, 6.12.75, 6.18.14, 6.19.4

How to fix

Upgrade to a fixed version: Linux kernel 5.10.252, 5.15.202, 6.1.165, 6.12.75. Check the vendor advisory for mitigations.

References

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