M2Team NanaZip up to 6.5.1742.0 UFS/FFS Image NanaZip.Codecs.Archive.Ufs.cpp memory allocation

CVSS Meta Temp Score
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CTI Interest Score
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2.7$0-$5k0.00

Summaryinfo

A vulnerability was found in M2Team NanaZip and classified as problematic. This vulnerability affects unknown code of the file NanaZip.Codecs.Archive.Ufs.cpp of the component UFS/FFS Image Handler. The manipulation results in memory allocation. This vulnerability is identified as CVE-2026-55781. The attack is only possible with local access. There is not any exploit available.

Detailsinfo

A vulnerability was found in M2Team NanaZip. It has been classified as problematic. Affected is an unknown code of the file NanaZip.Codecs.Archive.Ufs.cpp of the component UFS/FFS Image Handler. The manipulation with an unknown input leads to a memory allocation vulnerability. CWE is classifying the issue as CWE-789. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. This is going to have an impact on availability. CVE summarizes:

NanaZip is the 7-Zip derivative intended for the modern Windows experience. Prior to 6.5.1749.0, NanaZip's UFS and FFS image handler in NanaZip.Codecs.Archive.Ufs.cpp validates the superblock block size only against the MINBSIZE lower bound and does not validate the fs_fsize fragment size, allowing attacker-controlled 32-bit fields to flow into indirect-block, directory, and extraction buffer allocations. A tiny crafted UFS image can force multi-gigabyte allocations during open or extraction, causing memory exhaustion or process termination. This issue is fixed in version 6.5.1749.0.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-55781 since 06/17/2026. The exploitability is told to be easy. The attack needs to be approached locally. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 6.5.1749.0 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 2.8
VulDB Meta Temp Score: 2.7

VulDB Base Score: 2.8
VulDB Temp Score: 2.7
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory allocation
CWE: CWE-789 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: NanaZip 6.5.1749.0

Timelineinfo

06/17/2026 CVE reserved
07/10/2026 +23 days Advisory disclosed
07/10/2026 +0 days VulDB entry created
07/10/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-55781 (🔒)
GCVE (CVE): GCVE-0-2026-55781
GCVE (VulDB): GCVE-100-377556

Entryinfo

Created: 07/10/2026 19:29
Changes: 07/10/2026 19:29 (54)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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