CVE-2021-32671Public exploitNetwork attack vector

Unauthenticated script execution via unescaped translator parameters

Published Jun 7, 2021 · Updated Aug 3, 2024

Cross-site scripting in Flarum 1.0.0 through 1.0.1 allows remote attackers to execute JavaScript through crafted forum input. The Translator parameter-processing path passed string values into rendered HTML DOM nodes without escaping them, allowing markup in fields such as the forum search box to become executable content. No account is required; execution in a visitor's browser can issue same-origin AJAX requests that read or modify profile and forum data, with administrator sessions exposing administrative settings.

CVSS severity10.0
Critical
EPSS probability39.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Flarum 1.0.0 through 1.0.1 allows remote attackers to execute JavaScript through crafted forum input. The Translator parameter-processing path passed string values into rendered HTML DOM nodes without escaping them, allowing markup in fields such as the forum search box to become executable content. No account is required; execution in a visitor's browser can issue same-origin AJAX requests that read or modify profile and forum data, with administrator sessions exposing administrative settings.

The record

CVE
CVE-2021-32671
Published
Jun 7, 2021
Updated
Aug 3, 2024
Vendor
Flarum
Product
Flarum
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.0.0, < 1.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Flarum · Flarumversion=>= 1.0.0, < 1.0.2

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
10.0GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

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

Public exploit references

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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