{"answers":{"affected":"4 open source packages ship an affected version, including better-auth.","exploited":"There is no known exploitation of CVE-2026-45364 in the wild and no public exploit code.","fix":"Upgrade better-auth to a fixed version for your release line: 1.4.17 or 1.5.0-beta.9.","what":"CVE-2026-45364 is a high-severity vulnerability in better-auth, published on 28 May 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-2026-45364 and fix it if it is affected.\n\nWhat it is: CVE-2026-45364 is a high-severity vulnerability in better-auth, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-45364 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- better-auth (npm): affected all versions; fixed in 1.4.17\n- better-auth (npm): affected all versions; fixed in 1.4.17\n- better-auth (npm): affected from 1.5.0-beta.1; fixed in 1.5.0-beta.9\n- better-auth (npm): affected from 1.5.0-beta.1; fixed in 1.5.0-beta.9\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-2026-45364/ (Markdown: https://insights.sbomify.com/CVE-2026-45364/index.md)","id":"CVE-2026-45364","markdown":"https://insights.sbomify.com/CVE-2026-45364/index.md","name":"CVE-2026-45364","record":{"aliases":["GHSA-p6v2-xcpg-h6xw"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"TypeScript auth library","requires_auth":"none","summary":"Attackers can bypass rate limiting in Better Auth by rotating IPv6 addresses or varying their textual encoding, enabling brute-force attacks on authentication endpoints.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":7.3,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","version":"3.1"},"cwes":[{"id":"CWE-307","name":"Improper Restriction of Excessive Authentication Attempts"}],"description":"Better Auth is an authentication and authorization library for TypeScript. Prior to 1.4.17 and 1.5.0-beta.9, Better Auth's HTTP rate limiter keyed each request by the exact textual IP address it received in x-forwarded-for (or the configured IP-bearing header). IPv6 clients controlling a typical /64 allocation could rotate through 2^64 distinct source addresses without exhausting the per-address counter, defeating rate limiting on /sign-in/email, /sign-up/email, /forget-password, and every other path the limiter protects. The same bug allowed a single client to vary the textual encoding of one IPv6 address (uppercase, compression, IPv4-mapped, hex-encoded IPv4-in-IPv6) and produce multiple distinct keys. This vulnerability is fixed in 1.4.17 and 1.5.0-beta.9.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Better Auth: Rate limiter keys IPv6 addresses individually and is bypassable via prefix rotation","id":"CVE-2026-45364","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"security_feature_bypass","year":"2026"},"n_packages":4,"n_references":5,"next":{"headline":"Open WebUI: Authenticated users can bypass model access control via exposed query parameter","id":"CVE-2026-45365"},"packages":[{"ecosystem":"npm","fixed":["1.4.17"],"introduced":["0"],"last_affected":[],"package":"better-auth","purl":null,"source":"GHSA-p6v2-xcpg-h6xw"},{"ecosystem":"npm","fixed":["1.4.17"],"introduced":["0"],"last_affected":[],"package":"better-auth","purl":"pkg:npm/better-auth","source":"GHSA-p6v2-xcpg-h6xw"},{"ecosystem":"npm","fixed":["1.5.0-beta.9"],"introduced":["1.5.0-beta.1"],"last_affected":[],"package":"better-auth","purl":null,"source":"GHSA-p6v2-xcpg-h6xw"},{"ecosystem":"npm","fixed":["1.5.0-beta.9"],"introduced":["1.5.0-beta.1"],"last_affected":[],"package":"better-auth","purl":"pkg:npm/better-auth","source":"GHSA-p6v2-xcpg-h6xw"}],"prev":{"headline":"`jwt` (Ruby gem) - empty-key HMAC bypass","id":"CVE-2026-45363"},"products":["better-auth"],"published":"2026-05-28","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-29","vendors":["better-auth"]},"summary":"Attackers can bypass rate limiting in Better Auth by rotating IPv6 addresses or varying their textual encoding, enabling brute-force attacks on authentication endpoints.","url":"https://insights.sbomify.com/CVE-2026-45364/"}