Vulnerability in Nettle Project (CVE-2021-20305)
Summary
Vulnerability in Nettle Project (CVE-2021-20305). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-20305 has been found in Nettle Project.
Successful exploitation can lead to full system takeover. CVSS score: 8.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Nettle Project CVE-2021-20305" on the vendor's site.
CVE-2021-20305 (Nettle Project) — CWE-327 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-327) exists in Nettle Project.
Check the vendor advisory for the affected versions of Nettle Project.
Severity: High (CVSS 8.1/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Nettle Project を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2021-20305 nettle Fixed in: 3.7.2-r0
- Debian DEBIAN-CVE-2021-20305 nettle Fixed in: 3.7.2-1
References
- advisory security.netapp.com
- web bugzilla.redhat.com
- web lists.debian.org
- web lists.fedoraproject.org
- web security.gentoo.org
- web debian.org
- web cert-portal.siemens.com
- web nvd.nist.gov
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web security.netapp.com
- web github.com