MISP Reflected XSS in Taxonomy Tag Confirmation Forms (CVE-2026-103662) | HOL Guard CVE

Medium · CVSS 5.1CVE-2026-103662

MISP Reflected XSS in Taxonomy Tag Confirmation Forms

Answer in brief

CVE-2026-103662 records a Medium severity (CVSS 5.1) vulnerability in MISP Reflected XSS in Taxonomy Tag Confirmation Forms. The current sources do not mark it as known exploited. The current feed maps MISP/MISP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 1, 2026Updated Oct 1, 2026Source checked Oct 1, 2026First seen by HOL Oct 1, 2026Material review Oct 1, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps MISP/MISP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
MISP/MISPgeneric	>=0 <2.5.48	2.5.48

Recommended response

Check inventory. Check lockfiles and deployed manifests for MISP/MISP.
Review the reported fix. Source-reported solution: The vulnerability is remediated by HTML-encoding the user-supplied tag name value before it is interpolated into the confirmation form description text. This ensures that any HTML metacharacters in the input are rendered as inert text rather than executable markup, neutralizing the reflected XSS vector.

Evidence timeline and material changes

Published upstream
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 1, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source description

MISP contains a reflected cross-site scripting (XSS) vulnerability in the legacy taxonomy tag management confirmation forms (add tag and disable tag). The affected forms echoed a user-supplied tag name value from the request unescaped into the rendered HTML output. An attacker who can induce a site administrator to visit a crafted URL containing a malicious tag name parameter can execute arbitrary JavaScript in the administrator's browser session. Preconditions: - The target must be running a MISP instance with the legacy taxonomy tag confirmation views enabled. - The victim must be an authenticated site administrator. - The victim must navigate to the attacker-crafted URL (e.g., via a phishing link). Security impact: - Execution of arbitrary client-side script in the context of the administrator's browser. - Potential theft of session tokens, CSRF tokens, or other sensitive data accessible from the page. - Potential for performing privileged actions on behalf of the administrator within the MISP interface. Affected versions: <2.5.48.

Quoted source text, attributed separately from HOL analysis.