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CVE-2026-73311— XenForo < 2.3.13 OAuth2 Authorization Code Reuse

Quick assessment

Affected
XenForo XenForo
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

XenForo 2.3.13 之前的版本存在一个 OAuth2 授权码重用漏洞。攻击者可以通过提交一个已使用过的授权码，从而获取未经授权的令牌对。攻击者可利用系统在首次颁发令牌后未将授权码标记为“已消耗”或未使其失效这一缺陷，针对同一用户和权限范围获得一个独立的令牌对，从而绕过 OAuth2 授权码流程中“一次性使用”的保证。

CVSS 7.4 · High

Possible ATT&CK Techniques 1 AI

T1040 · Network Sniffing

Affected Version Matrix 1

VendorProduct Version RangeStatus
XenForo XenForo < 2.3.13 affected
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I. Basic Information for CVE-2026-73311

Vulnerability Information
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Vulnerability Title
XenForo < 2.3.13 OAuth2 Authorization Code Reuse
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
使用捕获-重放进行的认证绕过
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
XenForo XenForo 0 ~ 2.3.13 -

II. Public POCs for CVE-2026-73311

# POC Description Source Link Shenlong Link
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III. Intelligence Information for CVE-2026-73311

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Vendor Advisories for CVE-2026-73311 (1)

Exploits & Public PoCs for CVE-2026-73311 (1)

Security Blog Posts for CVE-2026-73311 (1)

Same Patch Batch · XenForo · 2026-09-08 · 14 CVEs total

CVE-2026-73315 8.6 HIGH XenForo < 2.3.13 SSRF via PayPal REST Webhook Handler
CVE-2026-73314 7.5 HIGH XenForo < 2.3.13 Signature Verification Bypass via PayPal REST Webhook
CVE-2026-73316 7.5 HIGH XenForo < 2.3.13 Payment Replay via PayPal REST Payment Provider
CVE-2026-73309 7.4 HIGH XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint
CVE-2026-73312 7.4 HIGH XenForo < 2.3.13 Refresh Token Replay via Expired Access Token
CVE-2026-74239 7.2 HIGH XenForo < 2.3.13 Path Traversal via Style Archive Importer on Windows
CVE-2026-73313 6.8 MEDIUM XenForo < 2.3.13 MFA Bypass via Passkey TFA Provider
CVE-2026-73321 6.5 MEDIUM XenForo < 2.3.13 Uncontrolled Recursion DoS via BBCode Parser
CVE-2026-73320 6.1 MEDIUM XenForo < 2.3.13 Unauthenticated Information Disclosure via Unfurl Endpoint
CVE-2026-73319 6.1 MEDIUM XenForo < 2.3.13 XSS via Dynamic Redirect Handler
CVE-2026-73310 5.9 MEDIUM XenForo < 2.3.13 OAuth2 Authorization Code Token Theft via redirect_uri Bypass
CVE-2026-73318 3.8 LOW XenForo < 2.3.13 Missing Authorization via force-agreement Controller
CVE-2026-73317 2.7 LOW XenForo < 2.3.13 Missing Authorization via ACP Cache-Rebuild Dispatcher

IV. Related Vulnerabilities

Same product: XenForo
Same vendor: XenForo
Same weakness: CWE-294

V. Comments for CVE-2026-73311

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