CVE-2021-37534Network attack vector

Stored XSS via unescaped forked cluster metadata

Published Jul 26, 2021 · Updated Aug 4, 2024

Stored XSS in MISP 2.4.146 and earlier allows remote authenticated users to execute JavaScript in another user's browser during cluster forking. The app/View/GalaxyClusters/add.ctp preview HTML-escapes scalar metadata but JSON-encodes array values without HTML escaping before inserting them into the page. An attacker must supply galaxy-cluster metadata and induce another authenticated user to fork the cluster; the payload then runs in that user's MISP origin.

CVSS severity5.4
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in MISP 2.4.146 and earlier allows remote authenticated users to execute JavaScript in another user's browser during cluster forking. The app/View/GalaxyClusters/add.ctp preview HTML-escapes scalar metadata but JSON-encodes array values without HTML escaping before inserting them into the page. An attacker must supply galaxy-cluster metadata and induce another authenticated user to fork the cluster; the payload then runs in that user's MISP origin.

The record

CVE
CVE-2021-37534
Published
Jul 26, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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