CVE-2026-55783
LowCVSS 2.4Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
A vulnerability in NanaZip (a 7-Zip fork for Windows) prior to version 6.5.1749.0 causes a process crash when testing or extracting WebAssembly, ElectronAsar, Zealfs, Romfs, Ufs, Littlefs, and DotNetSingleFile archives. The issue stems from unconditionally dereferencing the caller-supplied Indices pointer, which can be NULL when the archive engine signals extraction of all items.
Risk Assessment
An attacker can cause a denial of service (DoS) by crashing the NanaZip application when attempting to test or extract a crafted archive. The vulnerability does not allow remote code execution but can disrupt the tool's functionality.
Recommendation
Immediately update NanaZip to version 6.5.1749.0 or later, which includes a fix for the NULL pointer dereference issue.
Original NVD description (English source)
NanaZip is the 7-Zip derivative intended for the modern Windows experience. Prior to 6.5.1749.0, NanaZip's seven in-house IInArchive handlers in NanaZip.Codecs unconditionally dereference the caller-supplied Indices array inside Extract when the archive engine signals extract everything by passing Indices as NULL and NumItems as 0xFFFFFFFF. This causes a NULL pointer dereference in the standard Test archive or Extract all code path for WebAssembly, ElectronAsar, Zealfs, Romfs, Ufs, Littlefs, and DotNetSingleFile archives, resulting in a process crash. This issue is fixed in version 6.5.1749.0.