CVE-2026-53518

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 66% 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, nvd
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.1Exploit: None knownExposed: 0

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

Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint for the authorization_code grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two concurrent requests to pass the read step and mint independent access tokens, refresh tokens, and ID tokens; legacy /oauth2/token and /mcp/token paths in oidc-provider and mcp plugins share the same primitive. This issue is fixed in version 1.6.11.

CVSS v3
8.1
EG Score
8.1(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity81% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

July 7, 2026

Last Modified

July 21, 2026

Advisory Details (3)

Auto-updated Jul 15, 2026
Patch available. Sources: github, github_commit, github_release.
github Patch Available

@better-auth/oauth-provider: OAuth authorization-code grant allows concurrent redemption when two token requests race the find-then-delete primitive · Advisory · better-auth/better-auth · GitHub

https://github.com/better-auth/better-auth/security/advisories/GHSA-7w99-5wm4-3g79
github_release Patch Available

v1.6.11

Patch available: better-auth/better-auth v1.6.11

https://github.com/better-auth/better-auth/releases/tag/v1.6.11
github_commit

commit b4bc65a00778 (better-auth/better-auth)

Fix landed in better-auth/better-auth commit b4bc65a00778 — awaiting tagged release

https://github.com/better-auth/better-auth/commit/b4bc65a007784b2eb0efb459e5fa6fd8055d3ec9

Vendor Advisories for CVE-2026-53518(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
better-auth—1.6.11—
@better-auth/oauth-provider—1.6.11—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 43× 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. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
  5. 2026-09-06 14:07 UTCEG score recompute
  6. 2026-09-06 13:47 UTCEPSS rescore
  7. 2026-09-05 22:53 UTCEG score recompute
  8. 2026-09-04 05:06 UTCEPSS rescore
  9. 2026-09-02 14:12 UTCEPSS rescore
  10. 2026-09-01 13:54 UTCEPSS rescore
  11. 2026-09-01 04:40 UTCEPSS rescore
  12. 2026-08-30 19:17 UTCEPSS rescore
  13. 2026-08-30 07:42 UTCEG score recompute
  14. 2026-08-30 01:22 UTCEPSS rescore
  15. 2026-08-28 21:41 UTCEPSS rescore
  16. 2026-08-27 21:54 UTCEG score recompute
  17. 2026-08-27 14:25 UTCEPSS rescore
  18. 2026-08-27 01:53 UTCEG score recompute
  19. 2026-08-26 14:46 UTCEPSS rescore
  20. 2026-08-26 12:57 UTCEG score recompute
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-24 20:46 UTCEG score recompute
  23. 2026-08-24 09:48 UTCEG score recompute
  24. 2026-08-23 10:56 UTCEG score recompute
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 68 more
  1. 2026-08-22 02:04 UTCEG score recompute
  2. 2026-08-21 23:49 UTCEPSS rescore
  3. 2026-08-21 04:10 UTCEG score recompute
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 02:10 UTCEG score recompute
  6. 2026-08-19 17:04 UTCEPSS rescore
  7. 2026-08-18 20:47 UTCEG score recompute
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 14:36 UTCEG score recompute
  10. 2026-08-17 13:47 UTCEPSS rescore
  11. 2026-08-16 16:42 UTCEG score recompute
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 05:42 UTCEG score recompute
  14. 2026-08-16 02:14 UTCEPSS rescore
  15. 2026-08-15 07:49 UTCEG score recompute
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-13 22:59 UTCEG score recompute
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-12 14:09 UTCEG score recompute
  20. 2026-08-12 13:51 UTCEPSS rescore
  21. 2026-08-11 16:14 UTCEG score recompute
  22. 2026-08-11 05:18 UTCEG score recompute
  23. 2026-08-11 00:00 UTCEPSS rescore
  24. 2026-08-09 20:22 UTCEG score recompute
  25. 2026-08-09 13:46 UTCEPSS rescore
  26. 2026-08-08 22:29 UTCEG score recompute
  27. 2026-08-08 16:37 UTCEPSS rescore
  28. 2026-08-08 00:35 UTCEG score recompute
  29. 2026-08-06 15:44 UTCEG score recompute
  30. 2026-08-06 13:47 UTCEPSS rescore
  31. 2026-08-06 04:37 UTCEG score recompute
  32. 2026-08-05 19:17 UTCEPSS rescore
  33. 2026-08-04 19:30 UTCEG score recompute
  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 10:39 UTCEPSS rescore
  36. 2026-08-03 19:37 UTCEG score recompute
  37. 2026-08-03 10:36 UTCEPSS rescore
  38. 2026-08-02 10:43 UTCEG score recompute
  39. 2026-08-02 02:27 UTCEPSS rescore
  40. 2026-08-01 12:49 UTCEG score recompute
  41. 2026-08-01 04:16 UTCEPSS rescore
  42. 2026-07-31 03:13 UTCEG score recompute
  43. 2026-07-30 16:28 UTCEPSS rescore
  44. 2026-07-30 16:14 UTCEG score recompute
  45. 2026-07-30 04:48 UTCEG score recompute
  46. 2026-07-30 01:30 UTCEPSS rescore
  47. 2026-07-28 19:50 UTCEG score recompute
  48. 2026-07-28 15:37 UTCEPSS rescore
  49. 2026-07-27 21:48 UTCEG score recompute
  50. 2026-07-26 23:33 UTCEG score recompute
  51. 2026-07-26 14:54 UTCEPSS rescore
  52. 2026-07-26 12:34 UTCEG score recompute
  53. 2026-07-25 14:18 UTCEPSS rescore
  54. 2026-07-24 14:18 UTCEPSS rescore
  55. 2026-07-23 14:18 UTCEPSS rescore
  56. 2026-07-23 03:19 UTCEG score recompute▲ 0.50
  57. 2026-07-22 14:08 UTCEPSS rescore
  58. 2026-07-21 17:18 UTCNVD updateCVSS v3 → 8.1
  59. 2026-07-21 15:25 UTCEPSS rescore
  60. 2026-07-20 17:08 UTCEPSS rescore
  61. 2026-07-19 14:31 UTCEPSS rescore
  62. 2026-07-19 14:31 UTCEPSS rescore
  63. 2026-07-19 02:29 UTCEPSS rescore
  64. 2026-07-18 10:04 UTCEPSS rescore
  65. 2026-07-16 17:03 UTCEPSS rescore
  66. 2026-07-16 02:41 UTCEG score recompute▼ 0.50
  67. 2026-07-15 17:28 UTCMITRE cvelistV5CVSS v3 → 7.6 · CVSS v4 → 7.6
  68. 2026-07-07 21:13 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-53518?
CVE-2026-53518 is a high vulnerability published on July 7, 2026. Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint for the authorization_code grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two…
When was CVE-2026-53518 disclosed?
CVE-2026-53518 was first published in the National Vulnerability Database on July 7, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53518 actively exploited?
CVE-2026-53518 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.6% of all scored CVEs.
What is the CVSS score of CVE-2026-53518?
CVE-2026-53518 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-53518?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53518, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53518

Explore →

Is Your Infrastructure Affected by CVE-2026-53518?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs