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Threats / Unraid / CVE-2020-5847
CVE-2020-5847 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Unraid vulnerability

Unraid contains an insecure use of the PHP extract function allowing remote code execution as root. The vulnerability is exploited in the wild and can be chained with CVE-2020-5849 for initial access.

Verdict

Today item — known-exploited.

An unauthenticated attacker can exploit insecure variable handling in Unraid to achieve remote code execution with root privileges. Active exploitation in the wild combined with high EPSS score indicates immediate risk to exposed instances.

CISA KEV Yes · 2021-11-033EPSS 0.95844 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
585 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).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.95844 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Unraid, Unraid. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution 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 board
1

Front door — unauthenticated access narrative 1

Attacker
I gain initial access to the Unraid web interface through CVE-2020-5849 or direct network exposure.
Business
The organization's storage infrastructure becomes accessible to external threat actors without authentication.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I craft a malicious request that abuses the insecure extract function to inject arbitrary variables into the PHP execution context.
Business
The attacker bypasses application logic and gains ability to control program flow.
3

Lateral reach — past segmentation narrative 3

Attacker
I execute arbitrary code with root-level privileges on the Unraid system.
Business
Complete system compromise occurs, including data theft, encryption for ransom, lateral movement, or persistent backdoor installation.
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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • 585 reported-exploitation source(s)
  • Catalogued by mitre (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by mitreCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.