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Back to active CVEs
Unknown severity · Source severity not reportedCVE-2021-20305

CVE Program ContainerCVE-2021-20305

Answer in brief

CVE-2021-20305 records a Unknown severity vulnerability in CVE Program Container. The current sources do not mark it as known exploited. The current feed maps n/a/nettle (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic), Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Apr 5, 2021Updated Oct 14, 2026Source checked Oct 14, 2026First seen by HOL Oct 14, 2026Material review Oct 14, 2026
Upstream Advisory

Key facts

Risk
Unknown severitySource severity not reported
Exploitation
Not marked as known exploited
Affected software
4 mapped packages or products
Fix availability
Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps n/a/nettle (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic), Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
n/a/nettlegenericnettle 3.7.2Not reported
Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5
Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5
Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.0 <V3.1.5V3.1.5

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for n/a/nettle, Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP.
  2. 2Review the reported fix. Update Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5; Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5; Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Apr 5, 2021

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 14, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Oct 14, 2026

Sources and claim methodology

  • Source referencebugzilla.redhat.com
  • Source referencecert-portal.siemens.com
  • Source referencelists.debian.org
  • Source referencelists.fedoraproject.org
  • Source referencesecurity.gentoo.org
  • Source referencesecurity.netapp.com
  • Source referencedebian.org
Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • PeproDev Branches Map <= 3.0.1 - Authenticated (Contributor+) Stored Cross-Site ScriptingSame generic ecosystem
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  • Gstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: heap out-of-bounds write in asfmux due to incorrect utf-16 size calculation for non-bmp charactersSame generic ecosystem
  • WPCode 2.0.0 - 2.3.9 - Unauthenticated Snippet Suppression via Safe Mode BypassSame generic ecosystem
  • Stack overwrite from specially formatted base64 RDATA fieldSame generic ecosystem
  • Stack overwrite from a specially crafted and formatted SVCB or HTTPS RRSame generic ecosystem

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-327
Source
CVE List V5
Source checked
Oct 14, 2026
References
7 linked sources
Open source record