Remote resource disclosure via unchecked embed redirects
Published Nov 10, 2023 · Updated Feb 27, 2025
SSRF in Discourse stable before 3.1.3 and beta before 3.2.0.beta3 allows remote attackers to read remote resources via a redirected embed URL. TopicEmbed.find_remote resolves the initial URL, but uri.read follows a redirect without applying the destination checks to the redirect target. The attack requires the Embedding feature and user interaction; it exposes resources reachable from the forum server without writing data or disrupting service.
Summary
What happened
SSRF in Discourse stable before 3.1.3 and beta before 3.2.0.beta3 allows remote attackers to read remote resources via a redirected embed URL. TopicEmbed.find_remote resolves the initial URL, but uri.read follows a redirect without applying the destination checks to the redirect target. The attack requires the Embedding feature and user interaction; it exposes resources reachable from the forum server without writing data or disrupting service.
The record
- CVE
- CVE-2023-47121
- Published
- Nov 10, 2023
- Updated
- Feb 27, 2025
- Vendor
- Discourse
- Product
- Discourse
- Classifications
- CWE-918, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 10, 2023CVE publishedPublication date reported by the CVE source.
- Feb 27, 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.
- Affected versionversion=< 3.1.3
- Affected versionversion=>= 3.2.0.beta0, < 3.2.0.beta3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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