CVE-2026-55783 Null dereference in NanaZip
A NULL pointer dereference in NanaZip's custom archive handlers causes a process crash when extracting or testing specific archive types.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-55783?
CVE-2026-55783 is a low-severity vulnerability in M2Team NanaZip, published on 10 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-476
Which versions are affected by CVE-2026-55783?
How do I fix CVE-2026-55783?
No fix has been published for CVE-2026-55783 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-55783 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55783 exists.
Sources
Also known as GHSA-q67r-9cfh-xc29.