{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2025-71278/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[{"cvss":8.8,"id":"CVE-2025-71278"}],"_cs_exploited":false,"_cs_products":[],"_cs_severities":["high"],"_cs_tags":["cve-2025-71278","oauth2","xenforo","incorrect-authorization"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eXenForo, a popular forum software, has a security vulnerability (CVE-2025-71278) affecting versions prior to 2.3.5. Specifically, the vulnerability lies in the OAuth2 client application authorization process. OAuth2 clients can request scopes beyond those they are authorized to access. This vulnerability impacts any XenForo 2.3 installation utilizing OAuth2 clients prior to upgrading to version 2.3.5. Successful exploitation could allow malicious or compromised OAuth2 client applications to escalate privileges and access sensitive data or functionality within the XenForo forum.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker registers a malicious OAuth2 client application within the vulnerable XenForo instance.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts an OAuth2 authorization request, including scopes that the client should not be permitted to access according to XenForo\u0026rsquo;s intended authorization model.\u003c/li\u003e\n\u003cli\u003eThe vulnerable XenForo instance fails to properly validate the requested scopes against the client\u0026rsquo;s authorized permissions.\u003c/li\u003e\n\u003cli\u003eThe XenForo server grants access tokens with the requested, unauthorized scopes.\u003c/li\u003e\n\u003cli\u003eThe malicious OAuth2 client application uses the access token with the expanded privileges to interact with the XenForo API.\u003c/li\u003e\n\u003cli\u003eThe attacker performs actions they are not intended to be authorized for, such as accessing private user data, modifying forum settings, or performing administrative tasks depending on the scopes gained.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2025-71278 can lead to unauthorized data access, privilege escalation, and potential compromise of the XenForo forum. This can impact all users of the forum, leading to data breaches, defacement, or disruption of service. The severity depends on the unauthorized scopes obtained, but could range from accessing private messages to complete administrative control over the forum.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade XenForo installations to version 2.3.5 or later to remediate CVE-2025-71278 (reference: XenForo advisory in references).\u003c/li\u003e\n\u003cli\u003eImplement rate limiting on OAuth2 authorization requests to identify and mitigate potential abuse (reference: generic security best practice).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-04-01T01:16:40Z","date_published":"2026-04-01T01:16:40Z","id":"/briefs/2026-04-xenforo-oauth2-unauth-scope/","summary":"XenForo before 2.3.5 allows OAuth2 client applications to request unauthorized scopes, potentially allowing client applications to gain access beyond their intended authorization level due to improper authorization checks.","title":"XenForo OAuth2 Unauthorized Scope Request Vulnerability","url":"https://feed.craftedsignal.io/briefs/2026-04-xenforo-oauth2-unauth-scope/"}],"language":"en","title":"CraftedSignal Threat Feed — Cve-2025-71278","version":"https://jsonfeed.org/version/1.1"}