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VulnerabilityPublished

CVE-2026-27710: M2Team NanaZip · Integer Underflow

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 4% 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-2026-27710, organizations should upgrade NanaZip to versions 6.0.1638.0 or later, where the vulnerability is fixed. Until upgrades can be applied, restrict access to vulnerable NanaZip versions to trusted users only and avoid opening untrusted or suspicious archive files. Implement application whitelisting and endpoint protection to detect and block attempts to open malicious archives. Monitor system resource usage for unusual spikes that may indicate exploitation attempts. Consider sandboxing or isolating archive extraction processes to limit impact of potential crashes. Educate users about the risks of opening archives from unverified sources to reduce the likelihood of user interaction-based exploitation. Regularly review and update software inventories to identify vulnerable NanaZip installations. Finally, coordinate with software vendors and security teams to stay informed about patches and advisories related to NanaZip.

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, a denial-of-service vulnerability exists in NanaZip’s `.NET Single File Application` parser. A crafted bundle can force an integer underflow in header-size calculation and trigger an unbounded memory allocation attempt during archive open. Versions 6.0.1638.0 and 6.5.1638.0 fix the issue.

References

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