Executive brief
NanaZip is a file archiver for Windows based on 7-Zip. A security flaw in how it handles Android Verified Boot (AVB) image files allows an attacker to crash the application by providing a specially crafted file. This could lead to a denial of service where the user is unable to open certain archives or the application stops responding.
Technical details
A heap out-of-bounds read exists in the Android Verified Boot (AVB) vbmeta image parser (AvbHandler) due to a 32-bit unsigned integer overflow. Specifically, in the bounds check 'pos + ht.salt_len > descSize', an attacker can provide a large 'salt_len' value that causes the addition to wrap around to a small value, bypassing the validation. This leads to a 'memcpy' operation in 'CByteBuffer::CopyFrom' that attempts to read up to 4 GiB from a heap buffer that is typically only 64 KiB. While the primary impact is a deterministic application crash (DoS) upon hitting unmapped memory, it could theoretically lead to limited information disclosure of adjacent heap memory. The vulnerability is reachable via network delivery of a crafted file and requires minimal user interaction (opening the file). The issue is fixed in stable version 6.0.1698.0 and preview version 6.5.1742.0.
Affected products
- M2Team NanaZip 3.0.1000.0 to 6.0.1698.0
Timeline
- 2026-05-18: advisory: GitHub Security Advisory published by M2Team
- 2026-06-12: disclosed: CVE published to NVD