Threats / Unraid / CVE-2020-5847
CVE-2020-5847
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
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 · 2021-11-034EPSS 0.95844 (verify live)5CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3Exploit Weaponized · public exploit · Metasploit module · nuclei template11
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
643 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 0.95844 — 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: Unraid, Unraid. 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.
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 597 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 functional/weaponized public exploit). Catalog entries: Metasploit module, 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 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’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by mitreCNA
Credited with finding itNo finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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