Is CVE-2020-8515 in the CISA KEV catalog?

Yes. CVE-2020-8515 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03.

What is the CVSS severity of CVE-2020-8515?

CVE-2020-8515 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2020-8515?

CVE-2020-8515 has an EPSS score of 99.99% (100th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2020-8515?

No published fix for CVE-2020-8515 has been found yet. It is on the CISA Known Exploited Vulnerabilities list; federal agencies must remediate by 2022-05-03. Apply the vendor's mitigations per CISA's guidance.

CVE & CISA-KEV Catalog

CVE-2020-8515

CRITICALCISA KEVEPSS 100th pctl

9.8

CVSS v3

NVD

Description

DrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta devices allow remote code execution as root (without authentication) via shell metacharacters to the cgi-bin/mainfunction.cgi URI. This issue has been fixed in Vigor3900/2960/300B v1.5.1.

CWE-78OS Command Injection

How to fix

Actively exploited, no published fix found yet

CISA required action: Apply updates per vendor instructions.

Federal remediation due: 2022-05-03

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

99.99%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Multiple DrayTek Vigor Routers Web Management Page Vulnerability

DrayTek Vigor3900, Vigor2960, and Vigor300B routers contain an unspecified vulnerability that allows for remote code execution.

Apply updates per vendor instructions.

Remediation due: 2022-05-03

References

Exploit1

packetstormsecurity.com

Vendor Advisory1

draytek.com

Third-Party Advisory1

sku11army.blogspot.com

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-78 (OS Command Injection) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-1498	Critical	9.8	100%	KEV	Fix
CVE-2014-6271	Critical	9.8	100%	KEV	Fix
CVE-2019-16920	Critical	9.8	100%	KEV	-
CVE-2022-44877	Critical	9.8	100%	KEV	Fix
CVE-2020-9054	Critical	9.8	100%	KEV	Fix
CVE-2024-4577	Critical	9.8	100%	KEV + Ransom	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-07.