CVE-2026-55783 json
NanaZip: NULL pointer dereference in Extract() of all seven NanaZip custom archive handlers when extracting/testing the whole archive
published 2026-07-10 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42955
- cvss
- 2.4
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 6%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- m2team nanazip 6.5.1749.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/M2Team/NanaZip/security/advisories/GHSA-q67r-9cfh-xc29 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 2.4 | 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 |
| CNA | 4.0 | 2.4 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- M2Team NanaZip
Classification
- Weakness
-
- CWE-476 NULL Pointer Dereference
References
Sources
- CVE List CVE-2026-55783
- NVD CVE-2026-55783
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.