CVE-2023-22489Network attack vector

Unauthorized replies via null first-post authorization bypass

Published Jan 13, 2023 · Updated Mar 10, 2025

Missing authorization in Flarum 1.3.0 through 1.6.2 allows remote authenticated users to post replies through the REST API. PostReplyHandler treats a null discussion first_post_id as proof that a post is the discussion's first post and skips the actor's reply authorization assertion. Exploitation requires a visible discussion whose first post was permanently deleted while at least one approved reply remains; successful requests add unauthorized content and can trigger unsolicited email.

CVSS severity3.5
Low
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Flarum 1.3.0 through 1.6.2 allows remote authenticated users to post replies through the REST API. PostReplyHandler treats a null discussion first_post_id as proof that a post is the discussion's first post and skips the actor's reply authorization assertion. Exploitation requires a visible discussion whose first post was permanently deleted while at least one approved reply remains; successful requests add unauthorized content and can trigger unsolicited email.

The record

CVE
CVE-2023-22489
Published
Jan 13, 2023
Updated
Mar 10, 2025
Vendor
Flarum
Product
Flarum
Classifications
CWE-862, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 13, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 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=>= 1.3.0, < 1.6.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Flarum · Flarumversion=>= 1.3.0, < 1.6.3

Published CVSS scores

3.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.001Stored Data Manipulation

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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