CVE-2022-35924 is a critical-severity (CVSS 9.1) Improper Input Validation vulnerability in next-auth. A fix is available for next-auth — see the affected versions and patch details below.
Verification requests (magic link) sent to unwanted emails
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-35924.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-35924 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
next-authnpmDescription
Impact
next-auth users who are using the EmailProvider either in versions before 4.10.3 or 3.29.10 are affected.
If an attacker could forge a request that sent a comma-separated list of emails (eg.: [email protected],[email protected]) to the sign-in endpoint, NextAuth.js would send emails to both the attacker and the victim's e-mail addresses. The attacker could then login as a newly created user with the email being [email protected],[email protected]. This means that basic authorization like email.endsWith("@victim.com") in the signIn callback would fail to communicate a threat to the developer and would let the attacker bypass authorization, even with an @attacker.com address.
Patches
We patched this vulnerability in v4.10.3 and v3.29.10 by normalizing the email value that is sent to the sign-in endpoint before accessing it anywhere else. We also added a normalizeIdentifier callback on the EmailProvider configuration, where you can further tweak your requirements for what your system considers a valid e-mail address. (E.g.: strict RFC2821 compliance)
To upgrade, run one of the following:
npm i next-auth@latest
yarn add next-auth@latest
pnpm add next-auth@latest
(This will update to the latest v4 version, but you can change latest to 3 if you want to stay on v3. This is not recommended. v3 is unmaintained.)
Workarounds
If for some reason you cannot upgrade, you can normalize the incoming request like the following, using Advanced Initialization:
// pages/api/auth/[...nextauth].ts
function normalize(identifier) {
// Get the first two elements only,
// separated by `@` from user input.
let [local, domain] = identifier.toLowerCase().trim().split("@")
// The part before "@" can contain a ","
// but we remove it on the domain part
domain = domain.split(",")[0]
return `${local}@${domain}`
}
export default async function handler(req, res) {
if (req.body.email) req.body.email = normalize(req.body.email)
return await NextAuth(req, res, {/* your options */ })
}
References
- EmailProvider: https://next-auth.js.org/providers/email
- Normalize the email address: https://next-auth.js.org/providers/email#normalizing-the-email-address
- Email syntax: https://en.wikipedia.org/wiki/Email_address#Local-part
signIncallback: https://next-auth.js.org/configuration/callbacks#sign-in-callback- Advanced Initialization: https://next-auth.js.org/configuration/initialization#advanced-initialization
nodemaileraddress: https://nodemailer.com/message/addresses
For more information
If you have any concerns, we request responsible disclosure, outlined here: https://next-auth.js.org/security#reporting-a-vulnerability
Timeline
The issue was reported 26th of July, a response was sent out in less than 1 hour and after identifying the issue a patch was published within 5 working days.
Acknowledgments
We would like to thank Socket for disclosing this vulnerability in a responsible manner and following up until it got published.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next-auth | ≥ 4.0.0&&< 4.10.3 | 4.10.3npm install next-auth@4.10.3 |
| 📦npm | next-auth | all versions | 3.29.10npm install next-auth@3.29.10 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update next-auth to 4.10.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-35924 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-35924 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-35924. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-35924 in your dependencies?
O3 Security finds CVE-2022-35924 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.