dbcve.org
NanazipApplication · M2team

CVE-2026-42444

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 6.0.1698.0 or later.
See remediation →
58/100
Remediation priority · Elevated
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, a denial-of-service vulnerability exists in the littlefs filesystem image parser in NanaZip. The handler's Open method reads BlockCount directly from the attacker-controlled superblock without any validation against the actual file size or any upper-bound ceiling, then iterates BlockCount times, allocating a file-path entry per iteration. A crafted 44-byte littlefs image with BlockCount = 0xFFFFFFFF causes ~4 billion heap allocations, exhausting available memory. This vulnerability is fixed in 6.0.1698.0.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The littlefs filesystem image parser in NanaZip reads a BlockCount value from the superblock without validating it against file size or any upper bound. An attacker can provide a crafted 44-byte littlefs image with BlockCount=0xFFFFFFFF, causing approximately 4 billion heap allocations and exhausting available memory.

MitigationUpgrade to NanaZip version 6.0.1698.0 or later, which includes proper validation of the BlockCount field before iteration.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
NanazipApplication
Affected:>= 5.0.1252.0, < 6.0.1698.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify NanaZip is installed
    Check for NanaZip executable in common installation paths (e.g., C:\Program Files\NanaZip\NanaZip.exe, %LOCALAPPDATA%\NanaZip\NanaZip.exe) or search the Windows Registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall for NanaZip entries
    Affected if NanaZip is not found on the system, the user is not affected by this vulnerability
  2. Determine installed NanaZip version
    Right-click NanaZip.exe, select Properties, and check the File Version field on the Details tab. Alternatively, run: powershell (Get-Item 'C:\Program Files\NanaZip\NanaZip.exe').VersionInfo.FileVersion
    Affected if The version is greater than or equal to 5.0.1252.0 and less than 6.0.1698.0, the user is potentially affected
  3. Confirm littlefs support exists in this version
    Attempt to open a valid littlefs image file (.lfs or generic file) within NanaZip to verify the littlefs parser module is present and functional in this build
    Affected if The littlefs parser successfully reads a littlefs image without errors, the vulnerable code path is accessible and the user is affected if the version is in the affected range

The user is affected if NanaZip version is 5.0.1252.0 or higher but lower than 6.0.1698.0 and the littlefs filesystem parser is functional in the installed build.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.0.1698.0 or later
Fixed in 6.0.1698.0
Interim mitigation

Upgrade to NanaZip version 6.0.1698.0 or later, which includes proper validation of the BlockCount field before iteration.

Recommended fix High confidence

NanaZip 6.0.1698.0

  1. 1. Navigate to the NanaZip GitHub releases page at github.com/M2Team/NanaZip/releases
  2. 2. Download NanaZip version 6.0.1698.0 (or a later stable release if available)
  3. 3. Uninstall the current vulnerable version of NanaZip
  4. 4. Install the downloaded NanaZip 6.0.1698.0 or later version
Caveat Major version upgrade from 5.x to 6.x may introduce compatibility changes with existing archives or settings

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Nanazip Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-42444 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42444 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data