---
id: CVE-2021-20305
title: >-
  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 s…
summary: >-
  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 s…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-327
  - CWE-787
vendor: nettle_project
product: nettle
affected:
  - nettle < 3.7.2
  - fedora = 33
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - active_iq_unified_manager
  - ontap_select_deploy_administration_utility
  - debian_linux = 9.0
  - debian_linux = 10.0
patched:
  - nettle 3.7.2
published: '2021-04-05'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T11:16:51.937'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-20305'
references:
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1942533'
    label: secalert@redhat.com
  - url: 'https://lists.debian.org/debian-lts-announce/2021/09/msg00008.html'
    label: secalert@redhat.com
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQKWVVMAIDAJ7YAA3VVO32BHLDOH2E63/
    label: secalert@redhat.com
  - url: 'https://security.gentoo.org/glsa/202105-31'
    label: secalert@redhat.com
  - url: 'https://security.netapp.com/advisory/ntap-20211022-0002/'
    label: secalert@redhat.com
  - url: 'https://www.debian.org/security/2021/dsa-4933'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1942533'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/09/msg00008.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQKWVVMAIDAJ7YAA3VVO32BHLDOH2E63/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/202105-31'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20211022-0002/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2021/dsa-4933'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.01687
epssPercentile: 0.76441
ingestedAt: '2026-10-14T11:27:22.122Z'
---

## Overview

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.

## Affected

- `nettle < 3.7.2`
- `fedora = 33`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `active_iq_unified_manager`
- `ontap_select_deploy_administration_utility`
- `debian_linux = 9.0`
- `debian_linux = 10.0`

## Remediation

Upgrade past the affected range:

- `nettle 3.7.2`