Unauthenticated information disclosure via predictable unfurl IDs
Published Sep 8, 2026 · Updated Sep 9, 2026
Information disclosure in XenForo before 2.3.13 allows remote attackers to retrieve private unfurl previews via predictable IDs. The unfurl.php endpoint loads global UnfurlResult rows by attacker-supplied integer ID without checking a session, content visibility, parent object, or signed capability. Exploitation requires a pending preview for a previously unseen URL and accurate timing, but exposes rendered HTML, original URLs, and query strings from restricted content.
Summary
What happened
Information disclosure in XenForo before 2.3.13 allows remote attackers to retrieve private unfurl previews via predictable IDs. The unfurl.php endpoint loads global UnfurlResult rows by attacker-supplied integer ID without checking a session, content visibility, parent object, or signed capability. Exploitation requires a pending preview for a previously unseen URL and accurate timing, but exposes rendered HTML, original URLs, and query strings from restricted content.
The record
- CVE
- CVE-2026-73320
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- XenForo Ltd.
- Product
- XenForo
- Classifications
- CWE-639, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 2026Record 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=0 <2.3.13
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
- CVE-2026-73320 unfurl result proof of conceptfunctional · demonstrated
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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