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Vulnerability record · CVE-2026-73310 · published 8 September 2026

CVE-2026-73310: Xenforo incorrect authorization vulnerability

Xenforo · Xenforo

XenForo before 2.3.13 contains an authorization flaw in the OAuth2 token endpoint that allows attackers controlling any allowlisted redirect URI to bypass redirect URI binding by submitting a different allowlisted URI than the one recorded at authorization time. Attackers can exchange an intercepted authorization code using a mismatched redirect URI to steal OAuth2 tokens from intercepted authorization flows.

8.2 CVSS 4.0 High EPSS 0.49% · top 60.7% CWE-863 · Incorrect authorization
8.2CVSS 4.0 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
5References, 2 tagged exploit
11 Sep 2026Last modified by NVD

Description

XenForo before 2.3.13 contains an authorization flaw in the OAuth2 token endpoint that allows attackers controlling any allowlisted redirect URI to bypass redirect URI binding by submitting a different allowlisted URI than the one recorded at authorization time. Attackers can exchange an intercepted authorization code using a mismatched redirect URI to steal OAuth2 tokens from intercepted authorization flows.

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bombobombone.github.io/posts/cve-2026-73310/ ExploitThird Party Advisory
https://github.com/BomboBombone/CVE-2026-73310 ExploitThird Party Advisory
https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-token-theft-via-redirect-uri-bypass Third Party Advisory
https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.23 Release Notes
https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/ Release Notes

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2025-71279Xenforo improper authentication vulnerabilityXenForo before 2.3.7 contains a security issue affecting Passkeys that have been added to user accounts. An attacker may be able to compromise the se…EPSS 0.45%9.1CVE-2026-73311Xenforo authentication bypass by capture-replay vulnerabilityXenForo before 2.3.13 contains an OAuth2 authorization code reuse vulnerability that allows attackers to obtain unauthorized token pairs by submittin…EPSS 0.50%9.1CVE-2026-73312Xenforo authentication bypass by capture-replay vulnerabilityXenForo before 2.3.13 contains a refresh token replay vulnerability that allows attackers to reuse a refresh token multiple times by exploiting the f…EPSS 0.47%9.1CVE-2026-73309Xenforo vulnerabilityXenForo before 2.3.13 contains an authentication bypass vulnerability in the OAuth2 token endpoint that allows unauthenticated attackers to obtain va…EPSS 0.69%8.8CVE-2024-38457Xenforo cross-site request forgery vulnerabilityXenforo before 2.2.16 allows CSRF.EPSS 7.4%8.8CVE-2024-38458Xenforo code injection vulnerabilityXenforo before 2.2.16 allows code injection.EPSS 0.89%8.7CVE-2026-73314Xenforo vulnerabilityXenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook handler that allows unauthenticated attackers to bypas…EPSS 0.65%8.7CVE-2026-73316Xenforo insufficient verification of data authenticity vulnerabilityXenForo before 2.3.13 contains a payment replay vulnerability in the PayPal REST payment provider that allows attackers to process the same webhook p…EPSS 0.27%

Source: NIST National Vulnerability Database (record CVE-2026-73310), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.