Flarum
CVE-2023-22489
LOW
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK
1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 3.5 (LOW). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required. |
| Exploit ScenarioDerived | A remote attacker could access resources or perform actions without proper authorization checks by sending crafted requests to the affected application. |
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Alert meAnalysisAI
Flarum is a discussion platform for websites. Rated low severity (CVSS 3.5), this vulnerability is remotely exploitable, low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Implement role-based access control, validate authorization on every request server-side, apply principle of least privilege.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in composer
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Missing Authorization (CWE-862), which allows attackers to access resources or perform actions without proper authorization checks. Flarum is a discussion platform for websites. If the first post of a discussion is permanently deleted but the discussion stays visible, any actor who can view the discussion is able to create a new reply via the REST API, no matter the reply permission or lock status. This includes users that don't have a validated email. Guests cannot successfully create a reply because the API will fail with a 500 error when the user ID 0 is inserted into the database. This happens because when the first post of a discussion is permanently deleted, the first_post_id attribute of the discussion becomes null which causes access control to be skipped for all new replies. Flarum automatically makes discussions with zero comments invisible so an additional condition for this vulnerability is that the discussion must have at least one approved reply so that discussions.comment_count is still above zero after the post deletion. This can open the discussion to uncontrolled spam or just unintentional replies if users still had their tab open before the vulnerable discussion was locked and then post a reply when they shouldn't be able to. In combination with the email notification settings, this could also be used as a way to send unsolicited emails. Versions between v1.3.0 and v1.6.3 are impacted. The vulnerability has been fixed and published as flarum/core v1.6.3. All communities running Flarum should upgrade as soon as possible. There are no known workarounds. Affected products include: Flarum.
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Severity by source
AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Flarum is a discussion platform for websites. If the first post of a discussion is permanently deleted but the discussion stays visible, any actor who can view the discussion is able to create a new reply via the REST API, no matter the reply permission or lock status. This includes users that don't have a validated email. Guests cannot successfully create a reply because the API will fail with a 500 error when the user ID 0 is inserted into the database. This happens because when the first post of a discussion is permanently deleted, the first_post_id attribute of the discussion becomes null which causes access control to be skipped for all new replies. Flarum automatically makes discussions with zero comments invisible so an additional condition for this vulnerability is that the discussion must have at least one approved reply so that discussions.comment_count is still above zero after the post deletion. This can open the discussion to uncontrolled spam or just unintentional replies if users still had their tab open before the vulnerable discussion was locked and then post a reply when they shouldn't be able to. In combination with the email notification settings, this could also be used as a way to send unsolicited emails. Versions between v1.3.0 and v1.6.3 are impacted. The vulnerability has been fixed and published as flarum/core v1.6.3. All communities running Flarum should upgrade as soon as possible. There are no known workarounds.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Affected Products (CPE)NVD
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