CVE-2016-20021: portage Signature Bypass — Fix

Description

In Gentoo Portage before 3.0.47, there is missing PGP validation of executed code: the standalone emerge-webrsync downloads a .gpgsig file but does not perform signature verification. Unless emerge-webrsync is used, Portage is not vulnerable.

Is your site exposed to CVE-2016-20021?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-347 CWE-347

Affected Products

Vendor	Product	Versions
gentoo	portage	< 3.0.47

References

Advisories & Patches

https://bugs.gentoo.org/597800 https://bugs.gentoo.org/597800

Other References

https://gitweb.gentoo.org/proj/portage.git/tree/NEWS https://wiki.gentoo.org/wiki/Portage https://gitweb.gentoo.org/proj/portage.git/tree/NEWS https://wiki.gentoo.org/wiki/Portage

Frequently Asked Questions

What is CVE-2016-20021? +

In Gentoo Portage before 3.0.47, there is missing PGP validation of executed code: the standalone emerge-webrsync downloads a .gpgsig file but does not perform signature verification. Unless emerge-webrsync is used, Portage is not vulnerable. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2016-20021? +

CVE-2016-20021 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2016-20021? +

CVE-2016-20021 affects products from gentoo, specifically: portage. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2016-20021? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-44720

OpenLearnX is an open-source, decentralized learning and assessment platform. Prior to 2.0.4, a critical authentication vulnerability was identified in OpenLearnX …

CVE-2025-24800

Hyperbridge is a hyper-scalable coprocessor for verifiable, cross-chain interoperability. A critical vulnerability was discovered in the ismp-grandpa crate, that allowed …

CVE-2025-27498

aes-gcm is a pure Rust implementation of the AES-GCM. In decrypt_in_place_detached, the decrypted ciphertext (which is the correct ciphertext) is …

CVE-2024-11957

Improper verification of the digital signature in ksojscore.dll in Kingsoft WPS Office in versions equal or less than 12.1.0.18276 on …

CVE-2025-29774

xml-crypto is an XML digital signature and encryption library for Node.js. An attacker may be able to exploit a vulnerability …

CVE-2025-29775