CVE-2025-13434VulnerabilityPublished 20 Nov 2025

CVE-2025-13434: jameschz Hush Framework · Improper Neutralization of HTTP Headers for Scripting Syntax

Affects jameschz Hush FrameworkSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
jameschz Hush Framework	Affected =2.0	Fixed in–

AI-suggested

2) Implement strict validation and sanitization of the HTTP Host header at the application or web server level, ensuring only expected hostnames are accepted and any scripting syntax is neutralized. 3) Employ web application firewalls (WAFs) with custom rules to detect and block suspicious HTTP header manipulations indicative of exploitation attempts. 4) Monitor web server and application logs for anomalous Host header values or unusual HTTP header patterns. 5) Consider deploying reverse proxies or API gateways that enforce header normalization and validation before requests reach the vulnerable application. 6) If feasible, isolate or decommission applications using the vulnerable framework version until a patch or upgrade path is available. 7) Educate development teams on secure header handling practices to prevent similar issues in future code. 8) Stay alert for vendor updates or community patches and apply them promptly once available.

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.

Impact

For European organizations, the impact of CVE-2025-13434 can be significant if they rely on the jameschz Hush Framework 2.0 for web application development or hosting. Exploitation could allow attackers to inject malicious scripts or manipulate HTTP headers, leading to web cache poisoning, session hijacking, or cross-site scripting attacks. This can compromise user data confidentiality and integrity, damage organizational reputation, and potentially lead to regulatory non-compliance under GDPR if personal data is exposed. The remote, unauthenticated nature of the vulnerability increases the attack surface, making it easier for threat actors to exploit. The absence of vendor patches means organizations must rely on internal controls, increasing operational overhead. Given the framework's niche usage, the overall impact depends on the prevalence of the Hush Framework in European web infrastructure, but targeted attacks against vulnerable applications could disrupt services and erode trust.

References

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