CVE-2026-55783: low-severity vulnerability in M2Team NanaZip
NanaZip: NULL pointer dereference in Extract() of all seven NanaZip custom archive handlers when extracting/testing the whole archive
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 2.4epss 0.2%
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.
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Affected products
M2Team · NanaZipRelated CVEs — M2Team NanaZip
In the same product, most dangerous first.
CVE-2026-55780LOWNanaZip: Uncaught exception / unbounded allocation in NanaZip .NET single-file Extract() via unvalidated entry SizeEPSS 0.6%CVE-2026-54616HIGHNanaZip: Heap out-of-bounds read in NanaZip SquashFS LZ4 decompressor via unchecked negative return valueEPSS 0.4%CVE-2026-27114MEDIUMNanaZip has ROMFS Archive Infinite LoopEPSS 0.3%CVE-2026-44215MEDIUMNanaZip: Heap out-of-bounds write in NanaZip UFS directory parserEPSS 0.3%CVE-2026-47223MEDIUMNanaZip: Heap out-of-bounds read in NanaZip AVB hashtree descriptor parser via 32-bit unsigned integer overflowEPSS 0.2%CVE-2026-26282MEDIUMNanaZip has DotNet Single file OOB Heap ReadEPSS 0.2%