Description
MISP contains a reflected cross-site scripting (XSS) vulnerability in the event REST search export confirmation form. The view template app/View/Events/ajax/eventRestSearchExportConfirmationForm.ctp renders a URL-supplied event ID list into a single-quoted JavaScript string literal using PHP's json_encode() without any hex-encoding flags. By default, json_encode() escapes double quotes and backslashes but does not escape single quotes. Because the JavaScript string is delimited by single quotes, an attacker can inject a single-quote character to terminate the string literal and execute arbitrary JavaScript in the victim's browser session.

The vulnerability affects the Default and UiBeta themes, both of which render this view. The Overmind theme's own copy of the form already passed the value through an escaped data attribute and was not affected by this specific sink.

Preconditions: the victim must be an authenticated MISP user and must actively open or navigate to the attacker-crafted URL. The attacker does not require an account or any prior access to the MISP instance.

Security impact: successful exploitation allows execution of arbitrary JavaScript in the context of the MISP web application, potentially leading to session hijacking, unauthorized actions performed on behalf of the victim, exfiltration of sensitive data visible in the session, or further client-side attacks. The vulnerable component's own confidentiality, integrity, and availability are not directly compromised; the impact is on the underlying user session.
Published: 2026-09-22
Score: 5.1 Medium
EPSS: n/a
KEV: No
AI Analysis

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Remediation

Vendor Solution

The vulnerability is remediated by adding the JSON_HEX_TAG, JSON_HEX_APOS, JSON_HEX_QUOT, and JSON_HEX_AMP flags to the json_encode() call at the rendering sink. These flags cause angle brackets, single quotes, double quotes, and ampersands to be hex-encoded (e.g., ' becomes \u0027), preventing any of these characters from breaking out of the single-quoted JavaScript string literal and thereby eliminating the script injection vector.

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History

Tue, 22 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp

Tue, 22 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
Description MISP contains a reflected cross-site scripting (XSS) vulnerability in the event REST search export confirmation form. The view template app/View/Events/ajax/eventRestSearchExportConfirmationForm.ctp renders a URL-supplied event ID list into a single-quoted JavaScript string literal using PHP's json_encode() without any hex-encoding flags. By default, json_encode() escapes double quotes and backslashes but does not escape single quotes. Because the JavaScript string is delimited by single quotes, an attacker can inject a single-quote character to terminate the string literal and execute arbitrary JavaScript in the victim's browser session. The vulnerability affects the Default and UiBeta themes, both of which render this view. The Overmind theme's own copy of the form already passed the value through an escaped data attribute and was not affected by this specific sink. Preconditions: the victim must be an authenticated MISP user and must actively open or navigate to the attacker-crafted URL. The attacker does not require an account or any prior access to the MISP instance. Security impact: successful exploitation allows execution of arbitrary JavaScript in the context of the MISP web application, potentially leading to session hijacking, unauthorized actions performed on behalf of the victim, exfiltration of sensitive data visible in the session, or further client-side attacks. The vulnerable component's own confidentiality, integrity, and availability are not directly compromised; the impact is on the underlying user session.
Title MISP Reflected Cross-Site Scripting in Event Export Confirmation Form via Unescaped JSON
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: CIRCL

Published:

Updated: 2026-09-22T15:33:05.484Z

Reserved: 2026-09-22T13:01:42.885Z

Link: CVE-2026-95665

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-09-22T14:17:21.180

Modified: 2026-09-22T16:18:21.590

Link: CVE-2026-95665

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-22T17:15:15Z

Weaknesses