CVE-2026-112183

MISP CSS Injection via Remote Tag Colour in Event Preview

Published Oct 19, 2026 CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
MISP contains a CSS injection vulnerability in the remote event preview feature. When a user previews an event from a linked MISP server, the colour value associated with each remote tag is written directly into an inline CSS style attribute without sufficient validation. Although HTML entity encoding is applied, the value is interpreted as CSS within the style attribute, allowing a malicious or compromised linked server to inject arbitrary CSS declarations.

An attacker with the ability to create or modify tags on a linked MISP instance can craft a tag colour value containing CSS injection payloads. When a user on the local instance views the event preview, the injected CSS is rendered, potentially allowing UI manipulation, visual spoofing, or limited information disclosure through CSS-based techniques.

Preconditions:

- A linked MISP server relationship exists between the victim instance and the attacker-controlled instance.

- The attacker can create or modify tags on the linked server.

- A victim user views the remote event preview page.

Affected: <2.5.48.

Remediation

Vendor Solution

The fix introduces strict validation of the tag colour value before it is rendered into a CSS style attribute. Only values matching a valid six-digit hexadecimal colour pattern (e.g. #aabbcc) are accepted; any other value is replaced with a safe default (#ffffff). This prevents arbitrary CSS from being injected through the colour field, aligning the remote tag handling with the validation already applied to local tags.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description MISP contains a CSS injection vulnerability in the remote event preview feature. When a user previews an event from a linked MISP server, the colour value associated with each remote tag is written directly into an inline CSS style attribute without sufficient validation. Although HTML entity encoding is applied, the value is interpreted as CSS within the style attribute, allowing a malicious or compromised linked server to inject arbitrary CSS declarations. An attacker with the ability to create or modify tags on a linked MISP instance can craft a tag colour value containing CSS injection payloads. When a user on the local instance views the event preview, the injected CSS is rendered, potentially allowing UI manipulation, visual spoofing, or limited information disclosure through CSS-based techniques. Preconditions: - A linked MISP server relationship exists between the victim instance and the attacker-controlled instance. - The attacker can create or modify tags on the linked server. - A victim user views the remote event preview page. Affected: <2.5.48.
Title MISP CSS Injection via Remote Tag Colour in Event Preview
First Time appeared Misp
Misp misp
Weaknesses CWE-74
CPEs cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*
Vendors & Products Misp
Misp misp
References
Metrics cvssV4_0

{'score': 4.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Oct 19, 2026, 5:15 PM
Reserved
Oct 19, 2026, 9:15 AM
Status
Deferred
Published
Oct 19, 2026, 10:16 AM
Modified
Oct 19, 2026, 6:17 PM