CVE-2026-55783: NanaZip: NULL pointer dereference in Extract() of all seven NanaZip custom archive handlers when extracting/testing the whole archive
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
NanaZipto a version that resolves this vulnerability.Fixed in 6.5.1749.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-55783?
The severity of CVE-2026-55783 is classified as low with a CVSS score of 4.0.
What type of vulnerability is CVE-2026-55783?
CVE-2026-55783 is a Null Pointer Dereference vulnerability in NanaZip.
How do I fix CVE-2026-55783?
To fix CVE-2026-55783, upgrade NanaZip to version 6.5.1749.0 or later.
What software is affected by CVE-2026-55783?
NanaZip versions prior to 6.5.1749.0 are impacted by CVE-2026-55783.
What component of NanaZip does CVE-2026-55783 affect?
CVE-2026-55783 affects the Extract() function of the custom archive handlers in NanaZip.