CVE-2026-73420

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 57% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

July 23, 2026

Last Modified

August 14, 2026

Advisory Details (5)

Auto-updated Aug 13, 2026
Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

[email protected]

Patch available: nextauthjs/next-auth [email protected] (pre-release)

https://github.com/nextauthjs/next-auth/releases/tag/[email protected]
github_release Patch Available

[email protected]

Patch available: nextauthjs/next-auth [email protected]

https://github.com/nextauthjs/next-auth/releases/tag/[email protected]
github_commit Patch Available

commit a63eee12a1a2 (nextauthjs/next-auth)

Patch available: nextauthjs/next-auth @auth/[email protected] (contains commit a63eee12a1a2)

https://github.com/nextauthjs/next-auth/commit/a63eee12a1a20cb35209e44195b097868517b9a0
github_commit

commit 19d2feb24359 (nextauthjs/next-auth)

Fix landed in nextauthjs/next-auth commit 19d2feb24359 — awaiting tagged release

https://github.com/nextauthjs/next-auth/commit/19d2feb24359fa8c79418907fc68d9ec8152ca94
github Patch Available

Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass · Advisory · nextauthjs/next-auth · GitHub

https://github.com/nextauthjs/next-auth/security/advisories/GHSA-7rqj-j65f-68wh

Vendor Advisories for CVE-2026-73420(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 1 ecosystem)
npm(2)
PackageVulnerable rangeFixed inDependents
@auth/core—0.41.3—
next-auth—4.24.15—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 26× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-23 03:54 UTCEG score recompute
  2. 2026-08-23 00:19 UTCEPSS rescore
  3. 2026-08-22 01:30 UTCEG score recompute
  4. 2026-08-21 23:49 UTCEPSS rescore
  5. 2026-08-20 23:06 UTCEG score recompute
  6. 2026-08-20 22:56 UTCEPSS rescore
  7. 2026-08-19 20:33 UTCEG score recompute
  8. 2026-08-19 17:04 UTCEPSS rescore
  9. 2026-08-18 18:59 UTCEG score recompute
  10. 2026-08-18 13:49 UTCEPSS rescore
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-17 16:36 UTCEG score recompute
  13. 2026-08-17 13:47 UTCEPSS rescore
  14. 2026-08-16 17:44 UTCEG score recompute
  15. 2026-08-16 14:56 UTCEPSS rescore
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 02:26 UTCEG score recompute
  18. 2026-08-16 02:15 UTCEPSS rescore
  19. 2026-08-15 03:51 UTCEG score recompute
  20. 2026-08-15 01:31 UTCEPSS rescore
  21. 2026-08-14 16:32 UTCEG score recompute
  22. 2026-08-14 15:19 UTCEG score recompute
  23. 2026-08-13 22:25 UTCEG score recompute
  24. 2026-08-13 22:09 UTCEG score recompute▲ 9.10
  25. 2026-08-13 22:09 UTCMITRE cvelistV5CVSS v3 → 9.1 · CVSS v4 → 9.1
Show 1 more
  1. 2026-08-12 21:21 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-73420?
CVE-2026-73420 is a critical vulnerability published on July 23, 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…
When was CVE-2026-73420 disclosed?
CVE-2026-73420 was first published in the National Vulnerability Database on July 23, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73420 actively exploited?
CVE-2026-73420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 57.4% of all scored CVEs.
What is the CVSS score of CVE-2026-73420?
CVE-2026-73420 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-73420?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73420, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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