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Threats / QNAP / CVE-2018-19953
CVE-2018-19953 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

QNAP Network Attached Storage (NAS) vulnerability

Cross-site scripting vulnerability in QNAP NAS File Station allows remote attackers to inject malicious code, affecting stored data and system integrity.

Verdict

Today item, not a backlog item.

XSS flaw in QNAP File Station enables code injection attacks. Active exploitation and ransomware deployment observed in the wild. Attackers can compromise NAS devices and encrypt or exfiltrate stored files.

CISA KEV Yes · 2022-05-243Ransomware use Flagged3EPSS 0.23894 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
cybersecurityworks.com ↗cybersecurityworks.com ↗cisa.gov ↗Confirmed
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-24), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.23894 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
FIRST EPSS ↗High
Severity / affected
Affected: QNAP, Network Attached Storage (NAS). Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-79 Cross-site Scripting (XSS), CWE-80 CWE-80 — weakness family: Web / client.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-79 · Cross-site Scripting (XSS)CWE-80 · CWE-80Web / client
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 craft a malicious URL or upload content containing JavaScript that executes in the File Station web interface.
Business
User credentials and session tokens are harvested when administrators access the compromised interface.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I use stolen credentials to authenticate to the NAS and escalate privileges within the device.
Business
Attacker gains administrative access to the storage system and its configuration.
3

Lateral reach — past segmentation narrative 3

Attacker
I deploy ransomware or data exfiltration tools across the NAS volumes.
Business
Critical business files are encrypted or stolen, halting operations and triggering ransom demands or data breach notifications.
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)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • 3 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Catalogued by qnap (CNA)
  • Named finder/reporter credit (CVE.org)

    • 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.
    • Disclosure & credit2
    Catalogued by qnapCNA
    Credited with finding itIndependent Security Evaluatorsunspecified