Cross-domain iframe injection via prefix matching
Published Jul 30, 2024 · Updated Aug 2, 2024
Iframe injection in Discourse before 3.2.5 and 3.3.0.beta1 through 3.3.0.beta4 allows remote attackers to embed cross-domain content. The Markdown options builder treated allowed_iframes entries as URL prefixes without requiring a trailing slash, so approved hostnames also matched attacker-controlled lookalike domains. A visitor must render the crafted content, which bypasses the administrator's restriction on embedded origins.
Summary
What happened
Iframe injection in Discourse before 3.2.5 and 3.3.0.beta1 through 3.3.0.beta4 allows remote attackers to embed cross-domain content. The Markdown options builder treated allowed_iframes entries as URL prefixes without requiring a trailing slash, so approved hostnames also matched attacker-controlled lookalike domains. A visitor must render the crafted content, which bypasses the administrator's restriction on embedded origins.
The record
- CVE
- CVE-2024-39320
- Published
- Jul 30, 2024
- Updated
- Aug 2, 2024
- Vendor
- Discourse
- Product
- Discourse
- Classifications
- CWE-74, CWE-1021
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 30, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record 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=< 3.2.5
- Affected versionversion=>= 3.3.0.beta1, < 3.3.0.beta5
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.
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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