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: 0.7% (52nd percentile of EPSS-scored CVEs). 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: 0.7%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
52nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 23, 2026

Last Modified

September 18, 2026

Advisory Details (5)

Auto-updated Sep 16, 2026
Patch available. Sources: github_commit, github_release, github.
githubMentions a patch (unverified)

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
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

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 rangeFix by version rangeDependents
@auth/core—
  • 0.1.0 up to 0.41.3: fixed in 0.41.3
—
next-auth—
  • 4.10.3 up to 4.24.15: fixed in 4.24.15
  • 5.0.0-beta.1 up to 5.0.0-beta.32: fixed in 5.0.0-beta.32
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 37× 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. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:13 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
  4. 2026-10-06 15:18 UTCEPSS rescore
  5. 2026-10-05 17:43 UTCEPSS rescore
  6. 2026-10-04 23:22 UTCEPSS rescore
  7. 2026-10-04 08:21 UTCEG score recompute
  8. 2026-10-03 14:26 UTCEPSS rescore
  9. 2026-10-03 03:25 UTCEG score recompute
  10. 2026-10-01 19:50 UTCEPSS rescore
  11. 2026-10-01 06:17 UTCEG score recompute
  12. 2026-09-29 15:24 UTCEPSS rescore
  13. 2026-09-28 13:52 UTCEPSS rescore
  14. 2026-09-28 05:06 UTCEG score recompute
  15. 2026-09-27 13:48 UTCEPSS rescore
  16. 2026-09-26 15:59 UTCEPSS rescore
  17. 2026-09-23 22:21 UTCEG score recompute
  18. 2026-09-23 17:54 UTCEPSS rescore
  19. 2026-09-22 22:43 UTCEG score recompute
  20. 2026-09-21 21:09 UTCEPSS rescore
  21. 2026-09-20 20:16 UTCEPSS rescore
  22. 2026-09-20 01:47 UTCEG score recompute
  23. 2026-09-18 20:11 UTCEG score recompute
  24. 2026-09-18 19:28 UTCEPSS rescore
  25. 2026-09-18 03:06 UTCEG score recompute
Show 67 more
  1. 2026-09-17 02:02 UTCEG score recompute
  2. 2026-09-16 14:08 UTCEPSS rescore
  3. 2026-09-16 06:47 UTCEG score recompute
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-15 03:12 UTCEPSS rescore
  6. 2026-09-13 22:22 UTCEG score recompute
  7. 2026-09-12 16:46 UTCEG score recompute
  8. 2026-09-12 15:02 UTCEPSS rescore
  9. 2026-09-11 16:45 UTCEG score recompute
  10. 2026-09-11 14:53 UTCEPSS rescore
  11. 2026-09-10 15:10 UTCEG score recompute
  12. 2026-09-10 09:35 UTCEPSS rescore
  13. 2026-09-09 08:56 UTCEG score recompute
  14. 2026-09-08 22:01 UTCEPSS rescore
  15. 2026-09-07 21:30 UTCEG score recompute
  16. 2026-09-06 16:40 UTCEG score recompute
  17. 2026-09-06 13:48 UTCEPSS rescore
  18. 2026-09-05 19:28 UTCEG score recompute
  19. 2026-09-04 17:06 UTCEG score recompute
  20. 2026-09-04 13:16 UTCEG score recompute
  21. 2026-09-04 05:07 UTCEPSS rescore
  22. 2026-09-02 14:12 UTCEPSS rescore
  23. 2026-09-01 23:22 UTCEG score recompute
  24. 2026-09-01 13:54 UTCEPSS rescore
  25. 2026-09-01 04:40 UTCEPSS rescore
  26. 2026-09-01 04:40 UTCEPSS rescore
  27. 2026-08-30 19:33 UTCEG score recompute
  28. 2026-08-30 19:18 UTCEPSS rescore
  29. 2026-08-30 19:17 UTCEPSS rescore
  30. 2026-08-30 04:27 UTCEG score recompute
  31. 2026-08-30 01:22 UTCEPSS rescore
  32. 2026-08-30 00:33 UTCEG score recompute
  33. 2026-08-28 21:42 UTCEPSS rescore
  34. 2026-08-27 21:08 UTCEG score recompute
  35. 2026-08-27 14:25 UTCEPSS rescore
  36. 2026-08-26 19:55 UTCEG score recompute
  37. 2026-08-26 14:47 UTCEPSS rescore
  38. 2026-08-25 17:45 UTCEG score recompute
  39. 2026-08-25 13:49 UTCEPSS rescore
  40. 2026-08-24 15:06 UTCEG score recompute
  41. 2026-08-24 11:19 UTCEG score recompute
  42. 2026-08-23 03:54 UTCEG score recompute
  43. 2026-08-23 00:19 UTCEPSS rescore
  44. 2026-08-22 01:30 UTCEG score recompute
  45. 2026-08-21 23:49 UTCEPSS rescore
  46. 2026-08-20 23:06 UTCEG score recompute
  47. 2026-08-20 22:56 UTCEPSS rescore
  48. 2026-08-19 20:33 UTCEG score recompute
  49. 2026-08-19 17:04 UTCEPSS rescore
  50. 2026-08-18 18:59 UTCEG score recompute
  51. 2026-08-18 13:49 UTCEPSS rescore
  52. 2026-08-18 13:49 UTCEPSS rescore
  53. 2026-08-17 16:36 UTCEG score recompute
  54. 2026-08-17 13:47 UTCEPSS rescore
  55. 2026-08-16 17:44 UTCEG score recompute
  56. 2026-08-16 14:56 UTCEPSS rescore
  57. 2026-08-16 14:56 UTCEPSS rescore
  58. 2026-08-16 02:26 UTCEG score recompute
  59. 2026-08-16 02:15 UTCEPSS rescore
  60. 2026-08-15 03:51 UTCEG score recompute
  61. 2026-08-15 01:31 UTCEPSS rescore
  62. 2026-08-14 16:32 UTCEG score recompute
  63. 2026-08-14 15:19 UTCEG score recompute
  64. 2026-08-13 22:25 UTCEG score recompute
  65. 2026-08-13 22:09 UTCEG score recompute▲ 9.10
  66. 2026-08-13 22:09 UTCMITRE cvelistV5CVSS v3 → 9.1 · CVSS v4 → 9.1
  67. 2026-08-12 21:21 UTCEG score recompute

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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 on July 23, 2026, with the most recent update on September 18, 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 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73420?
CVE-2026-73420 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73420?
A fix for CVE-2026-73420 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-73420 are linked in the Vendor Advisories panel on this page.

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