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WS_FTP Server EUVDEUVD-2026-113023

| CVE-2026-90866 CRITICAL
Path Traversal (CWE-22)
2026-10-29 ProgressSoftware GHSA-p4xx-h8r7-vfh5
9.1
CVSS 3.1 · Vendor: ProgressSoftware
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Authenticate as delegated Host Administrator
  2. Exploit
    Submit crafted path with traversal sequences
  3. Execution
    Escape authorized scope on Windows host
  4. Impact
    Write or access files to gain code execution

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Path canonicalization, traversal prevention
MITRE ATT&CK

2 techniques across 2 tactics: Discovery, Collection

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the attacker to already hold a delegated Host Administrator account on WS_FTP Server (a scoped administrative role), so it is not reachable by anonymous or unauthenticated FTP users - this is the primary limiting factor and matches the PR:H metric. The affected deployment is WS_FTP Server on Windows at versions prior to 2024.0.7 (2024 branch) or prior to 2025.0.4 (2025 branch); patched builds remove the condition. The flaw is the server's failure to confine a delegated Host Administrator to their authorized scope when handling path input, allowing traversal to locations outside that scope; the exact crafted-input trigger is not detailed in the available sources. There is no required user interaction (UI:N) and no non-default feature toggle named in the description, but the delegation model itself - i.e., that such a scoped administrator account exists and is assigned - is the practical precondition.

Impact

Multiple signals point the same direction but with important caveats. The vendor-supplied CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H, base 9.1) describes a network-reachable, low-complexity flaw with a changed scope and full confidentiality/integrity/availability impact - consistent with a path traversal that escapes a delegated administrator's authorized boundary toward potential RCE. The one signal that materially tempers raw severity is PR:H: this is not an unauthenticated internet attack but one requiring an already-provisioned delegated Host Administrator account, so the realistic threat is a malicious or compromised scoped administrator escalating beyond their delegation rather than a mass-exploitable pre-auth bug. The vuln.today Decision label is act_now and the vendor (Progress) both reported and patched it, which argues for genuine priority. However, no EPSS score, no CISA KEV listing, and no public PoC/exploit reference are present in the input, so the act_now urgency rests on vendor/decision-framework judgment and the severity vector, not on observed exploitation or a known weaponized exploit. No SSVC exploitation/automatable/technical-impact fields were supplied, so that framework cannot be independently applied here. Net: a credible high-priority issue for organizations running WS_FTP Server with delegated Host Administrators, but the PR:H prerequisite and absence of exploitation evidence mean it is a privileged-insider / post-compromise escalation risk rather than a confirmed wormable pre-auth emergency - patch promptly per the act_now label.

Exploit ScenarioDerived

A delegated Host Administrator - an account intentionally scoped to administer only a specific host - supplies crafted path-traversal input to the WS_FTP Server management or file interface and reaches filesystem locations outside their authorized scope on the Windows server. By writing to or reading from unintended locations, the actor can escalate beyond their delegation and, per the vendor, potentially achieve remote code execution. No public exploit identified at time of analysis, so this scenario is derived from the vendor description and the AV:N/AC:L/PR:H CVSS vector rather than from observed exploit code.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.7% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 29, 2026

Path traversal in Progress WS_FTP Server on Windows lets a delegated Host Administrator escape the scope they were granted and reach files and locations outside it, which the vendor states can potentially lead to remote code execution. Only installations prior to 2024.0.7 on the 2024 branch and prior to 2025.0.4 on the 2025 branch are affected, and exploitation requires the attacker to already hold a delegated Host Administrator account - anonymous or ordinary FTP users cannot reach the flaw, matching the PR:H metric in the CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C vector with high confidentiality, integrity and availability impact. No public exploit code was identified at the time of analysis, and vendor-supplied patched builds resolve the condition.

RemediationAI

Upgrade to WS_FTP Server 2024.0.7 or later on the 2024 branch, or 2025.0.4 or later on the 2025 branch; the vendor states that patched builds remove the condition, and the Progress advisory at https://progress.lightning.force.com/lightning/r/Knowledge__kav/ka7Pb000001vl86IAA/view should be consulted for the download and upgrade procedure. Until the upgrade is applied, the leverage point is the precondition itself: because exploitation requires an already-assigned delegated Host Administrator account, review existing delegations and remove or tightly narrow any scoped Host Administrator role that is not actively required, accepting the operational trade-off that delegated staff lose their administrative access until the patch is deployed - this reduces exposure but is not a complete fix, since the underlying traversal is only removed by the patched build. Monitor for anomalies originating from delegated Host Administrator sessions, and treat any unexpected access to paths outside a delegated scope as a potential indicator of attempted exploitation.

Affected VersionsENISA

WS_FTP Server 0 <2024.0.7
WS_FTP Server 0 <2025.0.4

Affected Packages

euvd ws_ftp_server fix: 2024.0.7, 2025.0.4

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The flaw is a classic CWE-22 path traversal: when the server processes path input on behalf of a delegated Host Administrator - a scoped administrative role intended to confine that account to a defined subset of hosts and directories - it fails to hold the resulting operation inside that authorized scope. Because the app is deployed as WS_FTP Server on Windows, a successful escape lands the attacker in the server's broader file system context under the service account's privileges, which is the route the vendor links to possible remote code execution; the CVSS scope-changed (S:C) rating reflects that impact crossing from the delegated administrative boundary into the host itself. The CPE entry cpe:2.3:a:progress_software:ws_ftp_server:*:*:*:*:*:*:*:* is a wildcard match, so version identification must be done against the actual build rather than the CPE string; EUVD corroborates the two affected ranges as 0 <2024.0.7 and 0 <2025.0.4. The precise crafted input that triggers the traversal is not described in the available sources, and no non-default configuration toggle is named as a prerequisite - the practical precondition is that the delegation model is in use and a scoped Host Administrator account has been assigned.

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Severity by source

Vendor (ProgressSoftware) PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 9.1 CRITICAL

Network-facing FTP server (AV:N/AC:L) exploitable only by a privileged delegated Host Administrator (PR:H), escaping its authorized scope (S:C) toward full host compromise (C/I/A:H).

3.1 AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

Primary rating from Vendor (ProgressSoftware).

CVSS VectorVendor: ProgressSoftware

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch available
Oct 29, 2026 - 16:17 EUVD
CVE Published
Oct 29, 2026 - 15:52 cve.org
CRITICAL 9.1

DescriptionCVE.org

A path traversal vulnerability in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could allow a delegated Host Administrator to access locations outside their authorized scope, potentially enabling remote code execution.

Executive ViewAI

Why It Matters

Progress WS_FTP Server is affected by a critical path traversal vulnerability that allows delegated Host Administrators to exceed their intended permissions and potentially execute remote code. While exploitation requires an existing privileged account and no exploit code is publicly available, the flaw poses a significant risk to organizations using affected versions, as a compromised or malicious insider could escalate access and compromise the server. Leadership should prioritize patching to mitigate potential data breaches and operational disruptions.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.7%
Top 46% exploitable
Prevalence
Medium
enterprise managed-file-transfer server, moderate but not universal deployment
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.7%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

47
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

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