CVE-2026-73311
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OAuth2 Authorization Code Reuse in XenForo

Vulnerability report for CVE-2026-73311, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-08

Last updated on: 2026-09-09

Assigner: VulnCheck

Description

XenForo before 2.3.13 contains an OAuth2 authorization code reuse vulnerability that allows attackers to obtain unauthorized token pairs by submitting a previously used authorization code. Attackers can exploit the failure to invalidate or mark authorization codes as consumed after initial token issuance to receive an independent token pair for the same user and scopes, bypassing the single-use guarantee of the OAuth2 authorization code flow.

CVSS Scores

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Meta Information

Published
2026-09-08
Last Modified
2026-09-09
Generated
2026-09-09
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
xenforo xenforo to 2.3.13 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-294 A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).

Attack-Flow Graph

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