{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73311 exists.","fix":"No fix has been published for CVE-2026-73311 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-73311 is a critical authentication bypass vulnerability in XenForo, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-73311 and fix it if it is affected.\n\nWhat it is: CVE-2026-73311 is a critical authentication bypass vulnerability in XenForo, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73311 exists.\n\nAffected product: XenForo. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-73311/ (Markdown: https://insights.sbomify.com/CVE-2026-73311/index.md)","id":"CVE-2026-73311","markdown":"https://insights.sbomify.com/CVE-2026-73311/index.md","name":"CVE-2026-73311","record":{"aliases":["GHSA-mrq5-6m75-wpj5"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["account_takeover","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"XenForo forum software","requires_auth":"none","summary":"Attackers can reuse OAuth2 authorization codes to obtain unauthorized access tokens, bypassing single-use restrictions and potentially taking over user accounts.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[{"product":"xenforo","vendor":"xenforo"}],"cvss":{"score":9.1,"severity":"critical","source":"cna","vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-294","name":"Authentication Bypass by Capture-replay"}],"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.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2026-09-08","github_poc":1,"max_poc_stars":0,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-09-08T16:35:09Z","kind":"github_poc","ref":"https://github.com/BomboBombone/CVE-2026-73311","stars":0,"title":"Sanitized XenForo write-up and proof of concept for CVE-2026-73311."}],"tier":"weaponised"},"has_fix":null,"headline":"XenForo \u003c 2.3.13 OAuth2 Authorization Code Reuse","id":"CVE-2026-73311","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"XenForo \u003c 2.3.13 Refresh Token Replay via Expired Access Token","id":"CVE-2026-73312"},"packages":[],"prev":{"headline":"XenForo \u003c 2.3.13 OAuth2 Authorization Code Token Theft via redirect_uri Bypass","id":"CVE-2026-73310"},"products":["XenForo"],"published":"2026-09-08","related":[{"cvss_score":9.3,"headline":"XenForo Passkey Security Bypass","id":"CVE-2025-71279","kev_date_added":null,"published":"2026-04-01"},{"cvss_score":9.1,"headline":"XenForo \u003c 2.3.13 Authentication Bypass via OAuth2 Token Endpoint","id":"CVE-2026-73309","kev_date_added":null,"published":"2026-09-08"},{"cvss_score":9.1,"headline":"XenForo \u003c 2.3.13 Refresh Token Replay via Expired Access Token","id":"CVE-2026-73312","kev_date_added":null,"published":"2026-09-08"},{"cvss_score":8.8,"headline":"Xenforo before 2.2.16 allows CSRF.","id":"CVE-2024-38457","kev_date_added":null,"published":"2024-06-16"},{"cvss_score":8.8,"headline":"Code injection in n/a","id":"CVE-2024-38458","kev_date_added":null,"published":"2024-06-16"},{"cvss_score":8.7,"headline":"XenForo \u003c 2.3.13 Signature Verification Bypass via PayPal REST Webhook","id":"CVE-2026-73314","kev_date_added":null,"published":"2026-09-08"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-01","vendors":["XenForo"]},"summary":"Attackers can reuse OAuth2 authorization codes to obtain unauthorized access tokens, bypassing single-use restrictions and potentially taking over user accounts.","url":"https://insights.sbomify.com/CVE-2026-73311/"}