Use of a Broken or Risky Cryptographic Algorithm Affecting nettle package, versions <3.7-2.1ubuntu1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
1.74% (78th percentile)

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  • Snyk IDSNYK-UBUNTU2510-NETTLE-15734939
  • published21 Mar 2026
  • disclosed5 Apr 2021

Introduced: 5 Apr 2021

CVE-2021-20305  (opens in a new tab)
CWE-327  (opens in a new tab)

How to fix?

Upgrade Ubuntu:25.10 nettle to version 3.7-2.1ubuntu1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nettle package and not the nettle package as distributed by Ubuntu. See How to fix? for Ubuntu:25.10 relevant fixed versions and status.

A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply function being called with out-of-range scalers, possibly resulting in incorrect results. This flaw allows an attacker to force an invalid signature, causing an assertion failure or possible validation. The highest threat to this vulnerability is to confidentiality, integrity, as well as system availability.

CVSS Base Scores

version 3.1