{"answers":{"affected":"6 open source packages ship an affected version, including @auth/core and next-auth.","exploited":"There is no known exploitation of CVE-2026-73420 in the wild and no public exploit code.","fix":"Upgrade @auth/core to 0.41.3 or later.","what":"CVE-2026-73420 is a critical authentication bypass vulnerability in @auth core, published on 13 Aug 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-2026-73420 and fix it if it is affected.\n\nWhat it is: CVE-2026-73420 is a critical authentication bypass vulnerability in @auth core, published on 13 Aug 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-2026-73420 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- @auth/core (npm): affected from 0.1.0; fixed in 0.41.3\n- @auth/core (npm): affected from 0.1.0; fixed in 0.41.3\n- next-auth (npm): affected from 4.10.3; fixed in 4.24.15\n- next-auth (npm): affected from 4.10.3; fixed in 4.24.15\n- next-auth (npm): affected from 5.0.0-beta.1; fixed in 5.0.0-beta.32\n- next-auth (npm): affected from 5.0.0-beta.1; fixed in 5.0.0-beta.32\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-2026-73420/ (Markdown: https://insights.sbomify.com/CVE-2026-73420/index.md)","id":"CVE-2026-73420","markdown":"https://insights.sbomify.com/CVE-2026-73420/index.md","name":"CVE-2026-73420","record":{"aliases":["CLEANSTART-2026-PJ45513","CLEANSTART-2026-UY65626","ECHO-2dd4-1209-8fa6","GHSA-7rqj-j65f-68wh","MINI-9rhj-8fjf-x394","MINI-hqcv-vx43-gc7f","MINI-p7xj-prjj-q33p"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["account_takeover"],"network_reachable":"yes","non_default_config":false,"product_category":"NextAuth.js authentication library","requires_auth":"none","summary":"Attackers can hijack user accounts by exploiting Unicode normalization flaws in email validation to misroute magic-link sign-in emails.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":9.1,"severity":"critical","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-180","name":"Incorrect Behavior Order: Validate Before Canonicalize"}],"description":"NextAuth.js provides authentication for Next.js. Prior to @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, the defaultNormalizer used by the email and magic-link sign-in flow validates an address before applying Unicode normalization. An address can contain a Unicode character such as U+FF20 FULLWIDTH COMMERCIAL AT that is not ASCII at-sign but canonicalizes to an ASCII at-sign under NFKC or NFKD normalization. The address passes the normalizer's single-at-sign check, but a downstream sendVerificationRequest mail library or delivery service that normalizes the address can then see two at-sign separators and deliver the passwordless sign-in link to an attacker-controlled recipient. Applications are affected when the email provider uses the built-in normalizer rather than a custom normalizeIdentifier and the downstream sender applies Unicode normalization. An attacker who knows a victim's email address can request the misrouted magic link and sign in as the victim without victim interaction. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.","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":"NextAuth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass","id":"CVE-2026-73420","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":6,"n_references":6,"next":{"headline":"Auth.js: Configuration errors can cause existence-based auth checks to fail open (auth object populated with an error)","id":"CVE-2026-73421"},"packages":[{"ecosystem":"npm","fixed":["0.41.3"],"introduced":["0.1.0"],"last_affected":[],"package":"@auth/core","purl":null,"source":"GHSA-7rqj-j65f-68wh"},{"ecosystem":"npm","fixed":["0.41.3"],"introduced":["0.1.0"],"last_affected":[],"package":"@auth/core","purl":"pkg:npm/%40auth/core","source":"GHSA-7rqj-j65f-68wh"},{"ecosystem":"npm","fixed":["4.24.15"],"introduced":["4.10.3"],"last_affected":[],"package":"next-auth","purl":null,"source":"GHSA-7rqj-j65f-68wh"},{"ecosystem":"npm","fixed":["4.24.15"],"introduced":["4.10.3"],"last_affected":[],"package":"next-auth","purl":"pkg:npm/next-auth","source":"GHSA-7rqj-j65f-68wh"},{"ecosystem":"npm","fixed":["5.0.0-beta.32"],"introduced":["5.0.0-beta.1"],"last_affected":[],"package":"next-auth","purl":null,"source":"GHSA-7rqj-j65f-68wh"},{"ecosystem":"npm","fixed":["5.0.0-beta.32"],"introduced":["5.0.0-beta.1"],"last_affected":[],"package":"next-auth","purl":"pkg:npm/next-auth","source":"GHSA-7rqj-j65f-68wh"}],"prev":{"headline":"NextAuth.js: OAuth state, nonce, and PKCE check cookies are not bound to the provider that created them","id":"CVE-2026-73419"},"products":["core","next-auth"],"published":"2026-08-13","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":"total"},"state":"PUBLISHED","updated":"2026-08-14","vendors":["@auth","nextauthjs"]},"summary":"Attackers can hijack user accounts by exploiting Unicode normalization flaws in email validation to misroute magic-link sign-in emails.","url":"https://insights.sbomify.com/CVE-2026-73420/"}