CVE-2026-54616
The negative int is converted to the unsigned SizeT destLen and then truncated into outBufWasWrittenSize, causing ReadBlock to trust an attacker-inflated _cachedUnpackBlockSize.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 1.0.88.0 until stable version 6.0.1698.0 and preview version 6.5.1742.0, the Lz4Decode function in NanaZip.Core/SevenZip/CPP/7zip/Archive/SquashfsHandler.cpp rejects only a zero return from LZ4_decompress_safe even though malformed input produces a negative error value. The negative int is converted to the unsigned SizeT destLen and then truncated into outBufWasWrittenSize, causing ReadBlock to trust an attacker-inflated _cachedUnpackBlockSize. During fragment extraction, an attacker-controlled inode Offset can make memcpy read beyond the _cachedBlock heap allocation and place adjacent heap contents in the extracted file, or crash the process. This issue is fixed in stable version 6.0.1698.0 and preview version 6.5.1742.0.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:L
- EPSS
- 0.32% probability · 25th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Source
- security-advisories@github.com
References
- https://github.com/M2Team/NanaZip/commit/733e8570d2ba96c3e52aab44f5fd886775d5952f
- https://github.com/M2Team/NanaZip/commit/ce0322a1932e16a53e4a13e48bc61804c7826956
- https://github.com/M2Team/NanaZip/releases/tag/6.0.1698.0
- https://github.com/M2Team/NanaZip/releases/tag/6.5.1742.0
- https://github.com/M2Team/NanaZip/security/advisories/GHSA-95x5-qvvm-hmfp
- https://github.com/M2Team/NanaZip/security/advisories/GHSA-95x5-qvvm-hmfp
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.