CVE-2026-112183: MISP CSS Injection via Remote Tag Colour in Event Preview

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.3%

EPSS score, percentile 21.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

4.8 Medium

CVSS v4.0 base score, given by the CNA

What should I do?

The fix introduces strict validation of the tag colour value before it is rendered into a CSS style attribute. Full textSolution from the CVE record.

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• before 2.5.48

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Solution (from the CVE record)

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.

Advisories and patches

• Security patch (Patch)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

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…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-112183 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 19 Oct 2026.
• The CVE record carries a CVSS v4.0 base score of 4.8 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 21.4), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

MISP CSS Injection via Remote Tag Colour in Event Preview

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.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline