CVE Intelligence
High

CVE-2026-80656 — In the Linux kernel, the following vulnerability has been resolved: hfsplus: Add a…

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]

Published Aug 28, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database · CNA: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
—
Affected products not yet identified by the sources.
CVSS base
7.8
High · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Affected products have not been identified by the sources yet: follow the vendor advisory and map candidate assets by component name.
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Affected products not yet identified by the sources.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.8 CVSS 3.1 High 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.8
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 28, 2026 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No affected product/version with evidence in the sources.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-80656 is "In the Linux kernel, the following vulnerability has been resolved: hfsplus: Add a…", rated High. Affected products have not been identified by the sources yet. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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