CVE-2021-27917Network attack vector

Stored script execution via unescaped tracking URL

Published Sep 18, 2024 · Updated Sep 19, 2024

Stored XSS in Mautic 1.0.0-beta4 through 4.4.12 and 5.0.0 through 5.1.0 allows remote attackers to execute scripts. The /mtc/event endpoint stores a crafted page_url with contact activity, while affected views render derived identifiers and page-hit data without proper HTML encoding. Exploitation requires a Mautic user to view the affected contact or report data, causing the script to run in that user's browser context.

CVSS severity7.3
High
EPSS probability0.29%
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 Mautic 1.0.0-beta4 through 4.4.12 and 5.0.0 through 5.1.0 allows remote attackers to execute scripts. The /mtc/event endpoint stores a crafted page_url with contact activity, while affected views render derived identifiers and page-hit data without proper HTML encoding. Exploitation requires a Mautic user to view the affected contact or report data, causing the script to run in that user's browser context.

The record

CVE
CVE-2021-27917
Published
Sep 18, 2024
Updated
Sep 19, 2024
Vendor
Acquia
Product
Mautic
Classifications
CWE-79, CAPEC-63, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.0.0-beta4 << 4.4.13
  2. Affected versionversion=>= 5.0.0 << 5.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Acquia · Mauticversion=>= 1.0.0-beta4 << 4.4.13; version=>= 5.0.0 << 5.1.1

Published CVSS scores

7.3Mautic CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.6GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-63Cross-Site Scripting (XSS)
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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