Threats / DrayTek / CVE-2020-8515
CVE-2020-8515
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
DrayTek Multiple Vigor Routers vulnerability
DrayTek Vigor routers contain a command injection vulnerability enabling unauthenticated remote code execution. Active exploitation observed in the wild.
Verdict
Today item — known-exploited.
Critical remote code execution affecting multiple DrayTek Vigor router models. The vulnerability allows attackers to execute arbitrary commands on affected devices without authentication. High exploitation activity detected in operational networks.
CISA KEV Yes · 2021-11-034EPSS 0.99993 (verify live)5Exploit Weaponized · public PoC6CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
916 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.99993 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: DrayTek, Multiple Vigor Routers. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-78 OS Command Injection — weakness family: Injection.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 641 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a public proof-of-concept / detection template). Catalog entries: nuclei template. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify a DrayTek Vigor router exposed on the network and probe for the command injection vector.
Business
Network perimeter security fails to detect or block reconnaissance against critical routing infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious request that injects shell commands into an unvalidated input parameter.
Business
Input validation controls are absent, allowing arbitrary command execution with router privileges.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute commands to establish persistent access, modify routing tables, or exfiltrate traffic.
Business
Compromised router becomes a pivot point for lateral network movement and data interception.
4
Data at risk — exfiltration narrative 4
Attacker
I maintain access by installing backdoors or modifying firmware to survive reboots.
Business
Long-term network compromise enables sustained espionage, data theft, or infrastructure sabotage.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05