CVE-2024-21641Network attack vector

Open redirect via unchecked logout return URL

Published Jan 5, 2024 · Updated Jun 3, 2025

Open redirect in Flarum before 1.8.5 allows remote attackers to send visitors to arbitrary sites through the /logout route. LogOutController passes the unvalidated return query parameter directly into a RedirectResponse instead of restricting its host to an allowed domain. Guests are redirected immediately, while logged-in users must confirm logout; a crafted link can abuse the forum's trusted domain to steer visitors elsewhere.

CVSS severity4.7
Medium
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Flarum before 1.8.5 allows remote attackers to send visitors to arbitrary sites through the /logout route. LogOutController passes the unvalidated return query parameter directly into a RedirectResponse instead of restricting its host to an allowed domain. Guests are redirected immediately, while logged-in users must confirm logout; a crafted link can abuse the forum's trusted domain to steer visitors elsewhere.

The record

CVE
CVE-2024-21641
Published
Jan 5, 2024
Updated
Jun 3, 2025
Vendor
Flarum
Product
Flarum
Classifications
CWE-601, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record 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=< 1.8.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Flarum · Flarumversion=< 1.8.5

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
4.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/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 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-601URL Redirection to Untrusted Site ('Open Redirect')
T1204.001User Execution: Malicious Link

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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