Security readout for executives and security teams
Plain-English summary
This flaw affects Next.js applications using vulnerable Auth0 Next.js SDK versions. A malicious link could cause the login callback error page to render attacker-controlled script in a user’s browser. Business risk is account-facing web application compromise, especially where authentication flows are high trust.
Executive priority
Treat as high priority for affected customer-facing applications. Remediation is dependency-focused and should be scheduled promptly, with faster action for internet-facing authentication flows or high-value user populations.
Technical view
CVE-2021-32702 is reflected XSS in @auth0/nextjs-auth0 callback error handling. Vulnerable versions process the error query parameter into an HTML response without adequate escaping. The CVSS 3.1 score is 8.0 with network attack vector, no privileges required, user interaction required, and changed scope.
Likely exposure
Exposure is limited to applications using @auth0/nextjs-auth0 versions before 1.4.2, according to the affected range, unless custom error handling prevents returning the error message in HTML.
Exploitation context
The source bundle does not cite active exploitation and KEV is false. Exploitation requires user interaction and successful delivery of a crafted callback URL. The issue is still important because authentication pages are trusted and often reachable from the internet.
Researcher notes
The primary uncertainty is version wording: the description says versions through 1.4.1 are vulnerable, while one sentence says upgrade to 1.4.1. The affected range states versions below 1.4.2, so validate against Auth0’s advisory before closure.
Mitigation direction
- Upgrade @auth0/nextjs-auth0 to a non-affected version per Auth0 guidance.
- Confirm the exact patched version because the bundle contains conflicting upgrade wording.
- Use custom error handling that does not render raw error messages in HTML.
- Prioritize internet-facing Next.js applications with Auth0 login callbacks.
Validation and detection
- Inventory package-lock, yarn.lock, pnpm-lock, and deployed SBOMs for @auth0/nextjs-auth0 versions.
- Identify applications exposing the Auth0 Next.js callback handler.
- Review custom callback error handling for HTML rendering of untrusted error text.
- Confirm dependency upgrades are present in deployed artifacts, not only source control.
- Check application logs for unusual callback error-parameter activity without attempting reproduction.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-32702 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N1.65.8Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/auth0/nextjs-auth0/security/advisories/GHSA-954c-jjx6-cxv7CVE reference · x_refsource_CONFIRM
- https://github.com/auth0/nextjs-auth0/commit/6996e2528ceed98627caa28abafbc09e90163ccfCVE reference · x_refsource_MISC
- https://www.npmjs.com/package/%40auth0/nextjs-auth0CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.