What it is
CVE-2025-54123 is an unauthenticated vulnerability affecting SpectoLabs hoverfly. Hoverfly is an open source API simulation tool. In versions 1.11.3 and prior, the middleware functionality in Hoverfly is vulnerable to...
Vulnerability report
hoverfly Remote Code Execution
SpectoLabs / hoverfly · <= 1.11.3
Decision summary
Direct answers before the deeper technical record.
What it is
CVE-2025-54123 is an unauthenticated vulnerability affecting SpectoLabs hoverfly. Hoverfly is an open source API simulation tool. In versions 1.11.3 and prior, the middleware functionality in Hoverfly is vulnerable to...
Is it exploited?
Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is high. Also confirmed by third-party sources.
Who is affected?
SpectoLabs / hoverfly <= 1.11.3.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Hoverfly is an open source API simulation tool. In versions 1.11.3 and prior, the middleware functionality in Hoverfly is vulnerable to command injection vulnerability at `/api/v2/hoverfly/middleware` endpoint due to insufficient validation and sanitization in user input. The vulnerability exists in the middleware management API endpoint `/api/v2/hoverfly/middleware`. This issue is born due to combination of three code level flaws: Insufficient Input Validation in middleware.go line 94-96; Unsafe Command Execution in local_middleware.go line 14-19; and Immediate Execution During Testing in hoverfly_service.go line 173.
This allows an attacker to gain remote code execution (RCE) on any system running the vulnerable Hoverfly service. Since the input is directly passed to system commands without proper checks, an attacker can upload a malicious payload or directly execute arbitrary commands (including reverse shells) on the host server with the privileges of the Hoverfly process. Commit 17e60a9bc78826deb4b782dca1c1abd3dbe60d40 in version 1.12.0 disables the set middleware API by default, and subsequent changes to documentation make users aware of the security changes of exposing the set middleware API.
Exploitation evidence
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
The Shadowserver
A trusted third party reported exploitation.
Nuclei Templates
Public scanner or PoC coverage increases practical exploitability.
Per-source evidence links for KEV attestations are available through the Previdian Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2025-11-11 00:00 UTC |
Detection
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Request targets and User-Agents available in Pro. Callback host details available in Enterprise.
Nuclei template detected 01 Jun 2026.
View Nuclei template (opens in new tab)No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-54123.yaml | 01 Jun 2026 |
Risk and context
CVSS v3.1
Potential damage if exploited. Separate from whether attackers are using it.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
10.5%
Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.
These PoCs are unverified and could contain malware. Use at your own risk.
nuclei · Created Unknown
Timeline
14:21 UTC
Public proof-of-concept code published
15:34 UTC
Scanner coverage available
00:00 UTC
High-confidence, third-party attested exploitation
18:41 UTC
Vulnerability disclosed publicly
23:53 UTC
Identifier reserved by the CNA
Pro API
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
GET /api/v2/pro/kevs/CVE-2025-54123
Free JSON includes basic KEV fields{
"cve_id": "CVE-2025-54123",
"confidence": "High",
"cvss_score": 9.8,
"cvss_estimated": false,
"epss_score": 0.10543,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}