CVE-2026-24771
ADVISORY - githubSummary
Summary
A Cross-Site Scripting (XSS) vulnerability exists in the ErrorBoundary component of the hono/jsx library. Under certain usage patterns, untrusted user-controlled strings may be rendered as raw HTML, allowing arbitrary script execution in the victim's browser.
Details
The issue is in the ErrorBoundary component (src/jsx/components.ts). ErrorBoundary previously forced certain rendered output paths to be treated as raw HTML, bypassing the library's default escaping behavior. This could result in unescaped rendering when developers pass user-controlled strings directly as children, or when fallbackRender returns user-controlled strings (for example, reflecting error messages that contain attacker input).
This vulnerability is only exploitable when an application renders untrusted user input within ErrorBoundary without appropriate escaping or sanitization.
Impact
Successful exploitation may allow attackers to execute arbitrary JavaScript in the victim’s browser (reflected XSS). Depending on the application context, this can lead to actions such as session compromise, data exfiltration, or performing unauthorized actions as the victim.
Affected Components
- hono/jsx:
ErrorBoundarycomponent
GitHub
1.6
CVSS SCORE
4.7medium| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| hono | npm | - | - | <4.11.7 | 4.11.7 |
CVSS:3 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
A successful attack depends on conditions beyond the attacker's control, requiring investing a measurable amount of effort in research, preparation, or execution against the vulnerable component before a successful attack.
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.
Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.
An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 on the impacted component.
There is no impact to availability within the impacted component.
NIST
1.6