CVE-2021-27909Network attack vector

Client-side script execution via unsanitized bundle parameter

Published Aug 30, 2021 · Updated Sep 16, 2024

Reflected XSS in Acquia Mautic before 3.3.4 or 4.0.0 allows remote attackers to execute JavaScript through a password-reset URL. CommonController::delegateView lowercases the bundle query value and passes it as mauticContent without filtering script-significant characters. Exploitation requires a target to open the crafted link, after which the injected script runs in the target's browser under the Mautic origin.

CVSS severity6.3
Medium
EPSS probability4.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Acquia Mautic before 3.3.4 or 4.0.0 allows remote attackers to execute JavaScript through a password-reset URL. CommonController::delegateView lowercases the bundle query value and passes it as mauticContent without filtering script-significant characters. Exploitation requires a target to open the crafted link, after which the injected script runs in the target's browser under the Mautic origin.

The record

CVE
CVE-2021-27909
Published
Aug 30, 2021
Updated
Sep 16, 2024
Vendor
Acquia
Product
Mautic
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <3.3.4
  2. Affected versionversion=unspecified <4.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Acquia · Mauticversion=unspecified <3.3.4; version=unspecified <4.0.0

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.3MauticCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

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')
T1189Drive-by Compromise

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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