CVE-2026-47222: NanaZip: Heap out-of-bounds read in NanaZip AVB property descriptor parser via unsigned integer underflow
NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 3.0.1000.0 to before version 6.0.1698.0, a heap out-of-bounds read exists in the Android Verified Boot (AVB) vbmeta image parser in NanaZip (via the upstream 7-Zip AvbHandler). An unsigned integer underflow in a bounds check allows an attacker-controlled valuenumbytes field to pass validation, causing AddNameToString to read up to ~4 GiB past the end of a 64 KiB heap buffer. This causes a deterministic crash (denial of service) when opening a crafted .avb or .img file. This issue has been patched in stable version 6.0.1698.0 and preview version 6.5.1742.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
NanaZipto a version that resolves this vulnerability.Fixed in 6.0.1698.0 - Upgrade
Upgrade
NanaZipto a version that resolves this vulnerability.Fixed in 6.5.1742.0 - Compensating control
Do not open .avb or .img files from untrusted sources. If you cannot immediately update NanaZip, process AVB/vbmeta-containing files in an isolated environment (sandbox or VM) or restrict access to file handling (e.g., via host-based controls or file-scanning gateways) to prevent exposure to crafted files that can cause a crash.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-47222?
The severity of CVE-2026-47222 is medium with a score of 5.4.
How do I fix CVE-2026-47222?
To fix CVE-2026-47222, update NanaZip to version 6.0.1698.0 or later.
What type of vulnerability is CVE-2026-47222?
CVE-2026-47222 is categorized as a heap out-of-bounds read caused by an integer underflow.
Which versions of NanaZip are affected by CVE-2026-47222?
NanaZip versions from 3.0.1000.0 to before 6.0.1698.0 are affected by CVE-2026-47222.
What impact does CVE-2026-47222 have on users?
CVE-2026-47222 may allow attackers to read sensitive data from memory via the AVB property descriptor parser.