Hush Framework: Improper Neutralization of HTTP Headers for Scripting Syntax
CVE-2025-13434 is a high-severity improper neutralization of HTTP headers for scripting syntax vulnerability in Hush Framework from Jameschz, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Hush Framework versions: 2.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.5% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Hush Framework you run against the affected versions below, and install the vendor's latest release.
- 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 |
|---|---|---|---|
| Jameschz | Hush Framework | 2.0 | Not stated |
| Jameschz | Hush | 2.0 | 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
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 5.3 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | CNA (vuldb.com) |
Official description
A weakness has been identified in jameschz Hush Framework 2.0. The impacted element is an unknown function of the file Hush\hush-lib\hush\Util.php of the component HTTP Host Header Handler. This manipulation of the argument $_SERVER['HOST'] causes improper neutralization of http headers for scripting syntax. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be exploited. The vendor was contacted early about this disclosure but did not respond in any way.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of HTTP Headers for Scripting Syntax
The product does not neutralize or incorrectly neutralizes web scripting syntax in HTTP headers that can be used by web browser components that can process raw headers, such as Flash.
How developers prevent this class of flaw
- Carefully control data that is being placed both in HTTP response headers and in the HTTP response body to ensure that no scripting syntax is present, taking various encodings into account. Perform output validation in order to filter/escape/encode unsafe data that is being passed from the server in an HTTP response header.
- Disable script execution functionality in the clients' browser.
More Improper Neutralization of HTTP Headers for Scripting Syntax vulnerabilities (CWE-644)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vuldb.com/?id.332978Third Party Advisory, VDB Entry
- vuldb.com/?submit.687568Third Party Advisory, VDB Entry
Technical write-ups (may include proof of concept)
- github.com/lakshayyverma/CVE-Discovery/blob/main/hush.mdExploit, Third Party Advisory
Other references
- vuldb.com/?ctiid.332978Permissions Required, VDB Entry
Recent Improper Neutralization of HTTP Headers for Scripting Syntax vulnerabilities
- 8.5 High severity
- 7.5 High severity
- 8.8 High severity
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