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NVD / CVE Program· CNA GitHub_M

CVE-2026-42446: NanaZip: Stack out-of-bounds read in NanaZip ZealFS bitmap parser

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: M2Team NanaZip 6.0.1698.0.
  • Severity is disputed: the assigning authority (CNA) scores it 4.4, NVD 7.1.

Low priority for now. Upgrade to M2Team NanaZip 6.0.1698.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, a stack-based out-of-bounds read exists in the ZealFS filesystem image parser in NanaZip. The vulnerability is triggered when opening a crafted ZealFS v1 filesystem image. An attacker-controlled BitmapSize field in the file header drives an unbounded loop that reads past the end of a stack-allocated ZEALFS_V1_HEADER structure. This vulnerability is fixed in 6.0.1698.0.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
May 12, 2026
Updated
Oct 26, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.1
CNA · GitHub_M
4.4
2.7 point gap

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-42446

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
m2teamnanazip

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • m2team nanazip5.0.1252.0 and later · before 6.0.1698.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • M2Team NanaZip

    • >= 5.0.1250.0, < 6.0.1698.0affected

Same product

m2team: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-54616NanaZip: Heap out-of-bounds read in NanaZip SquashFS LZ4 decompressor via unchecked negative return value
    28Monitor
  • CVE-2026-44215NanaZip: Heap out-of-bounds write in NanaZip UFS directory parser
    28Monitor
  • CVE-2026-42445NanaZip: Uncontrolled recursion in NanaZip UFS directory traversal causes stack exhaustion
    22Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-42443May 12, 2026 · NanaZip: Integer divide-by-zero in NanaZip UFS inode offset calculation
    22Monitor
  • ← EarlierCVE-2026-42444May 12, 2026 · NanaZip: Unbounded resource consumption in NanaZip littlefs parser via attacker-controlled BlockCount
    22Monitor
  • Later →CVE-2026-47222Jun 12, 2026 · NanaZip: Heap out-of-bounds read in NanaZip AVB property descriptor parser via unsigned integer underflow
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
M2Team NanaZip6.0.1698.0 · descriptionVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-54616100 days apartNanaZip: Heap out-of-bounds read in NanaZip SquashFS LZ4 decompressor via unchecked negative return value
    28Monitor
  • CVE-2026-4722231 days apartNanaZip: Heap out-of-bounds read in NanaZip AVB property descriptor parser via unsigned integer underflow
    21Monitor
  • CVE-2026-4722331 days apartNanaZip: Heap out-of-bounds read in NanaZip AVB hashtree descriptor parser via 32-bit unsigned integer overflow
    21Monitor
  • CVE-2026-2770976 days apartNanaZip .NET Single-File Manifest Parser Vulnerable to Out-of-Bounds Read via Unchecked RelativePathLength
    20Monitor
  • CVE-2026-2771176 days apartNanaZip UFS Archive Parser Memory Corruption via Unvalidated Directory Record Length
    20Monitor
  • CVE-2026-4722431 days apartNanaZip: Heap buffer-overflow read in NanaZip LVM metadata CRC check
    17Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records