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Vulnerability · Published Apr 5, 2021 · Assigned by redhat

CVE-2021-20305

High 8.1

In plain English

A high-severity broken cryptography in nettle. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.7% (higher than 78% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)8.1High
Exploit odds (30 days)1.7%top 22.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20nettle3.7.2-r0ALPINE-CVE-2021-20305
Alpine:v3.21nettle3.7.2-r0ALPINE-CVE-2021-20305
Alpine:v3.22nettle3.7.2-r0ALPINE-CVE-2021-20305
Alpine:v3.23nettle3.7.2-r0ALPINE-CVE-2021-20305
Alpine:v3.24nettle3.7.2-r0ALPINE-CVE-2021-20305
Debian:12nettle3.7.2-1DEBIAN-CVE-2021-20305
Debian:13nettle3.7.2-1DEBIAN-CVE-2021-20305
Debian:14nettle3.7.2-1DEBIAN-CVE-2021-20305
Rocky Linux:8gnutls0:3.6.14-8.el8_3RLSA-2021:1206
Rocky Linux:8nettle0:3.4.1-4.el8_4RLSA-2021:1206

Affected products (as reported)

VendorProductVersions
n/a nettle nettle 3.7.2

Weakness: CWE-327

References