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VulnerabilityPublished

CVE-2026-27709: M2Team NanaZip · Out-of-bounds Read

Affects M2Team NanaZipSource CVE Database V5

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Not known to be exploited · CVSS 5.1 Medium : upgrade to 6.5.1638.0 or 6.0.1638.0 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
5.1Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.5.1638.0, 6.0.1638.0
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade NanaZip and m2team/NanaZip to 6.5.1638.0 or 6.0.1638.0.

Affected software

ProductAffectedFixed in
M2TeamNanaZipAffected
  • >=6.1 <6.5.1638.0
Fixed in
  • 6.5.1638.0
M2TeamNanaZipAffected
  • >=5.0.1252.0 <6.0.1638.0
Fixed in
  • 6.0.1638.0
GitHubm2team/NanaZippkg:github/m2team/NanaZipOther threatsAffected
  • >=5.0.1252.0 <6.0.1638.0
  • <6.5.1638.0
Fixed in
  • 6.0.1638.0
  • 6.5.1638.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-27709, organizations should immediately upgrade NanaZip to versions 6.0.1638.0 or 6.5.1638.0, where the vulnerability is patched. Until upgrades can be applied, restrict the use of NanaZip to trusted users and environments, and avoid opening untrusted or suspicious archive files. Implement endpoint security controls that detect and block attempts to open malformed archives. Educate users about the risks of opening archives from unknown or unverified sources to reduce the likelihood of social engineering exploitation. Additionally, consider application whitelisting to prevent execution of unauthorized versions of NanaZip. Monitoring for abnormal application crashes or memory access errors related to NanaZip can help detect exploitation attempts. Finally, maintain regular backups and incident response plans to recover from potential denial-of-service conditions.

Description

NanaZip is an open source file archive. Starting in version 5.0.1252.0 and prior to versions 6.0.1638.0 and 6.5.1638.0, NanaZip’s `.NET Single File Application` parser has an out-of-bounds read vulnerability in manifest parsing. A crafted bundle can provide a malformed `RelativePathLength` so the parser constructs a `std::string` from memory beyond `HeaderBuffer`, leading to crash and potential in-process memory disclosure. Versions 6.0.1638.0 and 6.5.1638.0 fix the issue.

References

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