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Back to active CVEs
Medium · CVSS 5.1CVE-2026-88921

MISP: Unescaped HTML Injection in PDF Report Element RenderingCVE-2026-88921

Answer in brief

CVE-2026-88921 records a Medium severity (CVSS 5.1) vulnerability in MISP: Unescaped HTML Injection in PDF Report Element Rendering. 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 Sep 10, 2026Updated Sep 10, 2026Source checked Oct 25, 2026First seen by HOL Sep 10, 2026Material review Sep 10, 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
PackageAffected rangeFixed version
MISP/MISPgeneric>=unspecified <2.5.462.5.46

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for MISP/MISP.
  2. 2Review the reported fix. Source-reported solution: The fix applies HTML entity encoding (via the h() helper, which wraps htmlspecialchars with ENT_QUOTES and UTF-8) to every user-controlled value interpolated into the HTML templates in the MISPElementHTMLFormatterTool. This ensures that attribute types, values, object names, relations, tag names, and colour values are treated as inert data and cannot inject markup or break out of the surrounding span/style context. The hardcoded sample values in the attribute() template are replaced with proper %s format placeholders so that the actual element data is rendered. Comprehensive unit tests are added to verify both correct rendering and escaping of hostile inputs across all four formatter methods.

Evidence timeline and material changes

  1. Published upstream

    Sep 10, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  2. Source modified

    Sep 10, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  3. First seen by HOL

    Sep 10, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
Upstream source description

MISP contains an HTML injection vulnerability in the MISPElementHTMLFormatterTool component, which is responsible for rendering MISP element references (attributes, objects, and tags) into inline HTML during PDF report export via the convert_markdown_to_pdf module. The attribute(), objectAttribute(), object(), and tag() methods interpolated user-controlled fields (attribute type, attribute value, object name, object relation, tag name, tag colour, and tag text colour) directly into HTML templates without applying HTML entity encoding. An authenticated user with the ability to create or modify MISP attributes, objects, or tags could embed arbitrary HTML markup in these fields. When a report containing such elements was exported to PDF, the unescaped content was rendered as live HTML rather than inert text, potentially injecting script tags, breaking the document structure, or altering the visual content of the exported report. Additionally, the attribute() method contained a template with hardcoded sample values ("domain-ip" and "google.com") instead of format placeholders, meaning every plain attribute reference in a PDF displayed the sample text rather than the actual indicator value, constituting a data-integrity defect in the exported document. The vulnerability requires an authenticated actor with write access to MISP elements and a subsequent PDF export of a report referencing those elements. The security impact is primarily to the integrity of the exported document and, depending on the HTML-to-PDF rendering engine, potential execution of injected markup during the conversion step. Version affected: ≤2.5.45

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • YesWiki before 4.7.0 Stored XSS via ImageField SVG UploadAlso CWE-79
  • YesWiki before 4.7.0 Stored XSS via filtertags Action ParametersAlso CWE-79
  • YesWiki 4.2.0 before 4.7.0 Stored XSS via Comment Raw-HTML SyntaxAlso CWE-79

Record context

Vulnerability class
XSS
EPSS
Not reported
CWE IDs
CWE-79, CWE-116
Source
CVE List V5
Source checked
Oct 25, 2026
References
1 linked source
Open source record