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NVD / CVE Program· CNA CIRCL

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

Noroxi assessment

Priority: Monitor (action score 20/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.49% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
  • Fixed version: MISP MISP 2.5.46.

Low priority for now. Upgrade to MISP MISP 2.5.46 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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

MediumCVSS 5.1 · v4.0—No exploit Fix available
Published
Sep 10, 2026
Updated
Sep 10, 2026
EPSS
0.4% · 42th percentile

Report tools

JSON

Action score

20

Monitor

Low priority for now.

CVSS
20 / 40 · 5.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CIRCL
5.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CIRCL). Independent of NVD's CPE analysis and usually ahead of it.

  • MISP MISP

    • unspecified and later · before 2.5.46affected · semver

Same product

misp: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-103655MISP TOTP Code Replay Allows Duplicate Authentication Within Validity Period
    37Monitor
  • CVE-2026-90961MISP LdapAuth and LinOTPAuth Authentication Bypass via Empty or Non-String Credentials
    37Monitor
  • CVE-2026-56422MISP Core: Mass Assignment and Object Re-ownership via Unvalidated Request Fields
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-86283Sep 6, 2026 · MISP UiBeta Collection View Bypasses Event ACL, Exposing Unauthorized Event Data
    28Monitor
  • ← EarlierCVE-2026-88915Sep 10, 2026 · MISP Event Template Instantiation Bypasses Sharing Group and Tagging Authorization
    28Monitor
  • Later →CVE-2026-90893Sep 14, 2026 · MISP UserSettingsController CSRF Protection Bypass on setTheme, setHomePage, and eventIndexColumnToggle Endpoints
    20Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
MISP MISP2.5.46Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-932967 days apartMISP Overmind: Stored Cross-Site Scripting via Unescaped Object Names in Statistics Legends
    34Monitor
  • CVE-2026-9427711 days apartStored Cross-Site Scripting in MISP Galaxy Matrix Statistics via Unescaped Galaxy Name
    25Monitor
  • CVE-2026-9437211 days apartStored Cross-Site Scripting via Unescaped Galaxy Cluster Tag Names in MISP Default Theme Galaxies Index
    25Monitor
  • CVE-2026-9437311 days apartMISP DOM-based Cross-Site Scripting via innerHTML in Contextual Menu
    25Monitor
  • CVE-2026-10338820 days apartMISP Stored Cross-Site Scripting via JavaScript URL in Galaxy Cluster Source Field
    24Monitor
  • CVE-2026-10490622 days apartMISP TAXII Object Viewer Stored XSS via Unescaped JSON Output
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
P
Scope
X

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records