{"basis":"claimed","id":"CVE-2026-121802","name":"Better Auth","vendorProject":"better-auth","product":"Better Auth","publishedAt":"2026-11-04","cvss":{"score":9.1,"severity":"CRITICAL","version":"3.1"},"exploited":null,"epss":null,"coverage":{"cloudflare":{"status":"none","firstOn":null,"daysToRule":null},"aws":{"status":"none","firstOn":null,"daysToRule":null},"azure":{"status":"none","firstOn":null,"daysToRule":null},"google":{"status":"none","firstOn":null,"daysToRule":null},"fastly":{"status":"none","firstOn":null,"daysToRule":null},"vercel":{"status":"blocks","firstOn":"2026-11-04","daysToRule":0},"f5":{"status":"none","firstOn":null,"daysToRule":null},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"none","firstOn":null,"daysToRule":null}},"title":null,"description":"@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any account's email address), because it signs a caller-supplied state value without checking whether that value had been issued by the server. NOTE: the application secret must be rotated after updating to a fixed version.","cwes":["CWE-346"],"vendors":[{"vendor":"cloudflare","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"aws","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"azure","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"google","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"fastly","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"vercel","status":"blocks","basis":"claimed","firstOn":"2026-11-04","firstIsNew":true,"daysToRule":0,"daysAtMost":null,"freePlan":false,"claims":[{"id":"356dcc38d062b9f5771caa027cf64f96e1acd816e2fa9a865b7bddc0942969b3","cve_id":"CVE-2026-121802","vendor":"vercel","product":"Vercel WAF","rule_id":null,"rule_name":"Better Auth November 2026 security release","change":"new","default_action":"Block","published_on":"2026-11-04","source_url":"https://vercel.com/kb/bulletin/better-auth-november-2026-security-release","source_title":"Better Auth November 2026 security release","excerpt":"Vercel created new rules to address these vulnerabilities and deployed them to the Vercel WAF to automatically protect all projects hosted on Vercel at no cost. Vercel deployed WAF rules that block the exploitable request patterns for the advisories that can be identified at the request layer, including the critical @better-auth/expo issue. Logic-level issues, such as session revocation with secondary storage, cannot be blocked by a WAF and are fixed only by upgrading.","first_seen_at":"2026-11-04T09:17:57.182Z"}]},{"vendor":"f5","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"akamai","status":"no_source","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"crs","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]}],"updatedAt":"2026-11-04T02:55:11.006Z","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","ssvc":null,"kevAction":null,"kevNotes":null,"references":[{"url":"https://github.com/better-auth/better-auth/security/advisories/GHSA-4wq4-2ppv-q3hg","name":null,"tags":[]},{"url":"https://github.com/better-auth/better-auth/blob/main/packages/expo/CHANGELOG.md","name":null,"tags":[]},{"url":"https://github.com/better-auth/better-auth/releases/tag/v1.7.16","name":null,"tags":[]}],"affected":[{"vendor":"better-auth","product":"Better Auth","affected":["before 1.7.16"],"fixed":[]}],"briefing":{"status":{"id":"monitor","label":"Monitor"},"why":"It is reachable over the network without credentials or any user interaction (CVSS 9.1). Exploitation in the wild is not established by CISA KEV.","who":"Teams running Better Auth (before 1.7.16). Prioritise internet-facing instances.","what_to_do":[{"text":"Apply the vendor's fix; the advisory lists the affected and fixed versions."},{"text":"Keep a WAF rule in place while you patch: Vercel blocks it by default. A WAF rule reduces exposure; it does not replace the patch.","href":"#edge","linkText":"Edge coverage"},{"text":"Check which WAF sits in front of your site and whether it covers this CVE.","href":"#check","linkText":"Check your domain"}],"evidence":[{"heading":"CVE record","text":"CVSS 3.1 9.1 (critical). Weakness: CWE-346.","links":[{"label":"CVE-2026-121802","href":"https://www.cve.org/CVERecord?id=CVE-2026-121802"},{"label":"NVD","href":"https://nvd.nist.gov/vuln/detail/CVE-2026-121802"}]},{"heading":"Exploit evidence","text":"No public exploit code found in Exploit-DB, Metasploit, nuclei-templates or GitHub. That does not mean none exists.","links":[]},{"heading":"CISA KEV","text":"Not in the KEV catalog (catalog 2026.11.03, checked 2026-11-04). Absence from KEV is not evidence that it cannot be exploited.","links":[{"label":"CISA KEV catalog","href":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog"}]},{"heading":"WAF vendor statements","text":"Vercel names it in a changelog. Quotes and dates below.","links":[{"label":"Vendor statements","href":"#evidence"}]}],"agent_prompt":"Assess whether the infrastructure available to you is affected by CVE-2026-121802 (Better Auth). Perform a read-only assessment within your authorized access. Do not send exploit traffic, scan third-party systems, change configuration or restart services.\n\n1. Verify the CVE record at https://www.cve.org/CVERecord?id=CVE-2026-121802 and the vendor advisory. Establish affected and fixed versions, including vendor backports. The record lists: better-auth Better Auth: affected before 1.7.16. Cite sources and retrieval dates; flag anything you cannot verify.\n2. Inventory deployments of Better Auth: asset, environment, owner where known, installed version or build, and how you confirmed it (package metadata, a version endpoint, image tags). An image tag alone does not prove the running version.\n3. Identify which deployments are reachable from the internet or untrusted networks, and through which paths (direct origin, load balancer, CDN or WAF).\n4. Assess compensating controls separately from patch status. Current edge WAF coverage for this CVE: Vercel: rule blocks by default. Live data: https://cve.vigilbase.com/api/v1/cves/CVE-2026-121802. Check whether the rule is enabled and in block mode on each path, and whether any path bypasses the WAF. A WAF rule is not a patch.\n5. Check logs on exposed instances for requests matching the public exploit, if your access allows.\n\nReturn a short summary and a table: asset | version/build | assessment (affected, fixed, not applicable, unknown) | exposure | compensating control | evidence | next action. List what you could not assess and the access needed to resolve it. Do not infer absence of compromise from patch status or a lack of alerts.\n\nRemediation guidance: Apply the vendor's fix; the advisory lists the affected and fixed versions. Keep a WAF rule in place while you patch: Vercel blocks it by default. A WAF rule reduces exposure; it does not replace the patch.\nMore: https://cve.vigilbase.com/cve/CVE-2026-121802"},"measured":[],"sightings":null,"social":{"total":10,"first_seen":"2026-11-04T02:52:40.000Z","daily":[{"day":"2026-10-22","posts":0},{"day":"2026-10-23","posts":0},{"day":"2026-10-24","posts":0},{"day":"2026-10-25","posts":0},{"day":"2026-10-26","posts":0},{"day":"2026-10-27","posts":0},{"day":"2026-10-28","posts":0},{"day":"2026-10-29","posts":0},{"day":"2026-10-30","posts":0},{"day":"2026-10-31","posts":0},{"day":"2026-11-01","posts":0},{"day":"2026-11-02","posts":0},{"day":"2026-11-03","posts":0},{"day":"2026-11-04","posts":10}],"top_posts":[{"source":"bluesky","kind":"post","url":"https://bsky.app/profile/thehackerwire.bsky.social/post/3mzhnqsmasc23","author":"thehackerwire.bsky.social","author_name":"TheHackerWire","avatar_url":"https://cdn.bsky.app/img/avatar/plain/did:plc:yhhqv2c64q5xv7mdwy6dbwqq/bafkreibnofwla3zl6epzaubi52gnzfchkqufk3k3eaktsy4ibsm7dtemeu","text":"🔴 CVE-2026-121802 - Critical (9.1)\n\n@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated c...\n\nhttps://www.thehackerwire.com/vulnerability/CVE-2026-121802/\n\n#infosec #cybersecurity #CVE #vulnerability #security #patchstack","engagement":0,"posted_at":"2026-11-04T05:48:25.000Z"},{"source":"mastodon","kind":"post","url":"https://mastodon.social/@thehackerwire/117556594746719941","author":"thehackerwire","author_name":"TheHackerWire","avatar_url":"https://files.mastodon.social/accounts/avatars/115/755/483/699/003/887/original/be4cc997d460de98.jpg","text":"🔴 CVE-2026-121802 - Critical (9.1) @better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any account's email address), because it signs a caller-supplied state value without checking whether that value had been issued by the…","engagement":0,"posted_at":"2026-11-04T05:48:02.149Z"},{"source":"bluesky","kind":"post","url":"https://bsky.app/profile/stackflag.bsky.social/post/3mzhispsqgp2z","author":"stackflag.bsky.social","author_name":"STACKFLAG","avatar_url":"https://cdn.bsky.app/img/avatar/plain/did:plc:zhe53h7ajlloep2oso5pqxzj/bafkreigtuhh5jkztpd2jbpwmsgwljrln6miskcl62es3xsgiziejo5gdve","text":"CVE-2026-121802 - better auth\nThe better-auth/expo component allows a malicious user to change the email address on any user account without logging in. This happens because it trusts a value supplied by the…\n\nToo many irrelevant or confusing CVEs? Use stackflag.com\n\n#betterauth…","engagement":0,"posted_at":"2026-11-04T04:20:00.000Z"},{"source":"x","kind":"post","url":"https://x.com/EnclaveRadar/status/2117833165674778706","author":"EnclaveRadar","author_name":"Enclave Radar","avatar_url":"https://pbs.twimg.com/profile_images/2116963272138121217/F3O3nWOo_bigger.jpg","text":"🆕 New CVE: CVE-2026-121802 (CVSS 9.1)\n@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any…\nRemote, no login needed.\n\n@better-auth/expo before 1.7.16 allows certain account-takeover outcomes…\n\nhttps://t.co/Iwml2HXpFr","engagement":0,"posted_at":"2026-11-04T04:15:48.000Z"},{"source":"bluesky","kind":"post","url":"https://bsky.app/profile/stemshop.bsky.social/post/3mzhi5ugsb52n","author":"stemshop.bsky.social","author_name":"stemshop.bsky.social","avatar_url":"https://cdn.bsky.app/img/avatar/plain/did:plc:6zpzsab44xavrl46jqvba5wb/bafkreid2zcmne7vr45ck2bkvmhnf4occned3jmavshzk2fh5j5qpbtluja","text":"🚨 CVE-2026-121802 — CVSS 9.1 CRITICAL\n\n@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of ...\n\n🔎 https://stemshop.top/cve/CVE-2026-121802\n\n#CVE #CyberSecurity #InfoSec","engagement":0,"posted_at":"2026-11-04T04:08:21.000Z"},{"source":"x","kind":"post","url":"https://x.com/ParameterWatch/status/2117830623385780393","author":"ParameterWatch","author_name":"Parameter Watch","avatar_url":"https://pbs.twimg.com/profile_images/2104287089877712896/fgf1DqZt_bigger.jpg","text":"⚠️ CVE-2026-121802 (9.1) ⚠️\n\nbetter-auth's Expo plugin lets an attacker change any account's email address without signing in.\n\nVersions before 1.7.16 are affected. Upgrade to 1.7.16. https://t.co/tLRRIpMSY5","engagement":0,"posted_at":"2026-11-04T04:05:42.000Z"},{"source":"bluesky","kind":"post","url":"https://bsky.app/profile/cve.skyfleet.blue/post/h7qbtuvcn4uyc","author":"cve.skyfleet.blue","author_name":"CVE Alerts ","avatar_url":"https://cdn.bsky.app/img/avatar/plain/did:plc:myutg2pwkjbukv7pq2hp5mtl/bafkreidzrx72dabuipp2ej2gldupqzv5nbtbez7tv4n26ekzjsot6ocdam","text":"CVE-2026-121802 - Better-Auth Expo Improper Authentication Verification Vulnerability\nCVE ID : CVE-2026-121802\n \n Published : Nov. 4, 2026, 2:36 a.m. | 28 minutes ago\n \n Description : @better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticat...","engagement":0,"posted_at":"2026-11-04T03:38:23.168Z"},{"source":"bluesky","kind":"post","url":"https://bsky.app/profile/offseq.bsky.social/post/3mzheeskp422q","author":"offseq.bsky.social","author_name":"OffSequence","avatar_url":"https://cdn.bsky.app/img/avatar/plain/did:plc:t5t6qep2vfipbi7f54demwev/bafkreidebkfyrafvzjuwvw3cnk6moxf6uzeg7hiubsqkthg653tnlrobxm","text":"better-auth Better Auth <1.7.16 hit by CRITICAL flaw (CVE-2026-121802): attackers can change any account’s email. Update to 1.7.16+ and rotate secrets ASAP. CVSS 9.1. https://radar.offseq.com/threat/cve-2026-121802-cwe-346-origin-validation-error-in-better-auth-better-auth-f3bb9…","engagement":0,"posted_at":"2026-11-04T03:00:40.081Z"},{"source":"x","kind":"post","url":"https://x.com/agentprime_io/status/2117814204866482638","author":"agentprime_io","author_name":"AgentPrime","avatar_url":"https://pbs.twimg.com/profile_images/2116608039792807936/JPVfQn5N_bigger.jpg","text":"🔴 Origin validation error in better-auth Better Auth (CVE-2026-121802)\nFix → 1.7.16\nhttps://t.co/EomBQaRxGT","engagement":0,"posted_at":"2026-11-04T03:00:28.000Z"},{"source":"x","kind":"post","url":"https://x.com/cvedotnow/status/2117812244293554218","author":"cvedotnow","author_name":"cve.now","avatar_url":"https://pbs.twimg.com/profile_images/2114469817906577408/drWsbSgs_bigger.jpg","text":"🆕 New CVE\nbetter-auth Better Auth: account takeover in mobile app authentication library (CVE-2026-121802)\nA remote, unauthenticated attacker can take over accounts, such as by changing any user's email address.\nPatch → 1.7.16\nhttps://t.co/cHpdVGQip7","engagement":0,"posted_at":"2026-11-04T02:52:40.000Z"}],"exploit_repositories":[]}}