CVE-2026-104901: MISP ID Translator: Unescaped Remote Event ID Enables Cross-Site Scripting via Linked Server

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 24.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

5.1 Medium

CVSS v4.0 base score, given by the CNA

What should I do?

The vulnerability is remediated by enforcing integer typing on the remote event ID at the point where it enters the application data structure in the controller … 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 vulnerability is remediated by enforcing integer typing on the remote event ID at the point where it enters the application data structure in the controller, and by applying HTML output encoding (the h() helper) to all user-visible fields (remote_id, server_id) in both the default and Overmind-themed ID Translator views. This ensures that even if a remote server returns non-numeric or markup-laden data, it cannot be interpreted as HTML by the browser.

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 cross-site scripting (XSS) vulnerability in the ID Translator feature. When a user views the ID Translator page, the application queries linked (remote) MISP servers for corresponding event identifiers. The event ID returned by the remote server was rendered in the HTML output without proper output encoding. A malicious or compromised linked server could return a crafted event ID…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-104901 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 2 Oct 2026.
• The CVE record carries a CVSS v4.0 base score of 5.1 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 24.7), 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 ID Translator: Unescaped Remote Event ID Enables Cross-Site Scripting via Linked Server

MISP contains a cross-site scripting (XSS) vulnerability in the ID Translator feature. When a user views the ID Translator page, the application queries linked (remote) MISP servers for corresponding event identifiers. The event ID returned by the remote server was rendered in the HTML output without proper output encoding. A malicious or compromised linked server could return a crafted event ID containing arbitrary HTML or JavaScript markup. This markup would be rendered in the browser of any user in the host organization who views the ID Translator page, enabling session hijacking, credential theft, or other client-side attacks. Preconditions: - The victim must be an authenticated user of the host MISP instance. - A linked server must be configured on the host instance. - The victim must navigate to the ID Translator page for a given event. Affected versions: <2.5.48.

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

Timeline