Answer in brief
CVE-2026-73420 records a Critical severity vulnerability in NextAuth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass. The current sources do not mark it as known exploited. The current feed maps @auth/core (generic), nextauthjs/next-auth (generic), @auth/core (npm), @auth/core (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-73420 records a Critical severity vulnerability in NextAuth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass. The current sources do not mark it as known exploited. The current feed maps @auth/core (generic), nextauthjs/next-auth (generic), @auth/core (npm), @auth/core (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps @auth/core (generic), nextauthjs/next-auth (generic), @auth/core (npm), @auth/core (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| @auth/coregeneric | >= 0.1.0, < 0.41.3 | Not reported |
| nextauthjs/next-authgeneric | < 4.24.15 || >= 5.0.0-beta.4, < 5.0.0-beta.32 | Not reported |
| @auth/corenpm | >=0.1.0 <0.41.3 | 0.41.3 |
| @auth/corenpm | >=0.1.0,<0.41.3 | 0.41.3 |
| next-authnpm | >=4.10.3 <4.24.15 | 4.24.15 |
| next-authnpm | >=5.0.0-beta.1 <5.0.0-beta.32 | 5.0.0-beta.32 |
| next-authnpm | >=4.10.3,<4.24.15 | 4.24.15 |
| next-authnpm | >=5.0.0-beta.1,<=5.0.0-beta.31 | 5.0.0-beta.32 |
Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 12, 2026
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.
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps @auth/core (generic), nextauthjs/next-auth (generic), @auth/core (npm), @auth/core (npm) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| @auth/coregeneric | >= 0.1.0, < 0.41.3 | Not reported |
| nextauthjs/next-authgeneric | < 4.24.15 || >= 5.0.0-beta.4, < 5.0.0-beta.32 | Not reported |
| @auth/corenpm | >=0.1.0 <0.41.3 | 0.41.3 |
| @auth/corenpm | >=0.1.0,<0.41.3 | 0.41.3 |
| next-authnpm | >=4.10.3 <4.24.15 | 4.24.15 |
| next-authnpm | >=5.0.0-beta.1 <5.0.0-beta.32 | 5.0.0-beta.32 |
| next-authnpm | >=4.10.3,<4.24.15 | 4.24.15 |
| next-authnpm | >=5.0.0-beta.1,<=5.0.0-beta.31 | 5.0.0-beta.32 |
Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 12, 2026
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.
Quoted source text, attributed separately from HOL analysis.