hoverfly: Improper Neutralization of Special Elements used in an OS Command
CVE-2025-54123 is a critical-severity improper neutralization of special elements used in an OS command vulnerability in hoverfly from SpectoLabs, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected hoverfly versions: <= 1.11.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 10.9% chance of exploitation within 30 days, which is in the top 4.06% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of hoverfly you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| SpectoLabs | hoverfly | <= 1.11.3 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
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 before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Other vulnerabilities in hoverfly
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 7.8 High severity
- 8.8 High severity
- 7.2 High severity
- 8.5 High severity
- 9.8 Critical severity
- 8.8 High severity
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