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Full vulnerability report · 2026
CVE-2026-67394High confidence

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5

WebPros · Plesk

9.0CriticalCVSS 4.0
Recommended action
Within 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 1.29% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs WebPros Plesk and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-68921

No EUVD known-exploited evidence

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5. The vulnerability allows a customer or reseller with shell access (or allowed to change their own shell access) to elevate privileges to the root account on the hosting server.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.0 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Mitigation available
01

What, why and how

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5. The vulnerability allows a customer or reseller with shell access (or allowed to change their own shell access) to elevate privileges to the root account on the hosting server.

What

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5. The vulnerability allows a customer or reseller with shell access (or allowed to change their own shell access) to elevate privileges to the root account on the hosting server.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5. The vulnerability allows a customer or reseller with shell access (or allowed to change their own shell access) to elevate privileges to the root account on the hosting server.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → gain additional privileges
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-78 ↗

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCHighSubsequent-system confidentiality: A successful attack can cause a major loss.SIHighSubsequent-system integrity: A successful attack can cause a major loss.SAHighSubsequent-system availability: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkPrivilege escalationCWE-78
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-68921Official EUVD mapping

A critical local privilege escalation via OS command injection vulnerability has been discovered in Plesk for Linux, affecting all versions from 18.0.34 before 18.0.79.9 and 18.0.80.5. The vulnerability allows a customer or reseller with shell access (or allowed to change their own shell access) to elevate privileges to the root account on the hosting server.

Official EUVD record ↗
Canadian Centre for Cyber Security · English · AV26-866WebPros security advisory (AV26-866)

As of September 1, 2026, WebPros is affected by vulnerabilities in the following product:

Official advisory ↗
CSIRT Italia · Italian · risolta-vulnerabilita-in-plesk-2Risolta vulnerabilità in Plesk

Aggiornamenti di sicurezza risolvono una vulnerabilità in Plesk, software per la gestione di server web. Tale vulnerabilità, qualora sfruttata, potrebbe consentire ad un utente malintenzionato di elevare i propri privilegi sui sistemi interessati

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Mitigation available
Affected
Plesk: 18.0.34 < 18.0.79.9, 18.0.80 < 18.0.80.5
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
The Cyber Centre encourages users and administrators to review the provided web link and apply any necessary updates as they become available.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 1 Sept 2026 · Last source change 1 Sept 2026, 13:14 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-01
European sourceENISA EUVD · EUVD-2026-68921
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD awaiting enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2026-68921 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-68921"}
    ENISA EUVD ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Canadian Centre for Cyber Security ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2026-68921↗Canadian Centre for Cyber Security remediation guidance↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-67394 · cve.blacktree.nl