CVE-2026-42444

Application hang via unchecked BlockCount allocation loop

Published May 12, 2026 · Updated May 12, 2026

Resource exhaustion in M2-Team NanaZip from 5.0.1252.0 to before 6.0.1698.0 allows attackers to hang the application via a crafted littlefs image. The littlefs handler's Open method accepts the superblock BlockCount without checking the file size or applying a ceiling, then allocates one path entry per declared block. Opening the 44-byte file is required; BlockCount 0xFFFFFFFF drives about four billion heap allocations, exhausts memory, and does not enable code execution.

CVSS severity3.3
Low
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in M2-Team NanaZip from 5.0.1252.0 to before 6.0.1698.0 allows attackers to hang the application via a crafted littlefs image. The littlefs handler's Open method accepts the superblock BlockCount without checking the file size or applying a ceiling, then allocates one path entry per declared block. Opening the 44-byte file is required; BlockCount 0xFFFFFFFF drives about four billion heap allocations, exhausts memory, and does not enable code execution.

The record

CVE
CVE-2026-42444
Published
May 12, 2026
Updated
May 12, 2026
Vendor
M2-Team
Product
NanaZip
Classifications
CWE-770, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 5.0.1250.0, < 6.0.1698.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

M2-Team · NanaZipversion=>= 5.0.1250.0, < 6.0.1698.0

Published CVSS scores

3.3GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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