CVE-2026-18500

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 95% 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
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.

@fastify/jwt is a JSON Web Token plugin for Fastify. In versions before 10.2.2, a per-request verification key passed to request.jwtVerify({ key }) is silently overridden by the plugin's globally configured secret, because the option merge applies the global key last. Applications that use different keys for different authorization domains, for example separate user and admin keys, therefore accept a token signed with the global key on a route that explicitly requires another key. This lets an ordinary authenticated user cross a key-based trust boundary without knowing either secret. The issue is fixed in @fastify/jwt 10.2.2, where an explicit per-call key takes precedence over the global secret. Users should upgrade to 10.2.2.

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
5%
KEV
Not listed

Published

August 15, 2026

Last Modified

September 4, 2026

Advisory Details (2)

Auto-updated Aug 15, 2026
Patch available. Sources: github.
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html
github Patch Available

@fastify/jwt vulnerable to authorization bypass via global secret overriding the per-request key · Advisory · fastify/fastify-jwt · GitHub

https://github.com/fastify/fastify-jwt/security/advisories/GHSA-j4cx-787j-xjqg

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 49× 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. 2026-09-19 16:32 UTCEG score recompute
  2. 2026-09-19 04:40 UTCEG score recompute
  3. 2026-09-18 19:27 UTCEPSS rescore
  4. 2026-09-18 03:42 UTCEG score recompute
  5. 2026-09-16 16:06 UTCEG score recompute
  6. 2026-09-16 14:07 UTCEPSS rescore
  7. 2026-09-16 05:14 UTCEPSS rescore
  8. 2026-09-15 14:31 UTCEG score recompute
  9. 2026-09-14 02:54 UTCEG score recompute
  10. 2026-09-13 16:46 UTCEPSS rescore
  11. 2026-09-12 15:17 UTCEG score recompute
  12. 2026-09-12 15:00 UTCEPSS rescore
  13. 2026-09-11 15:32 UTCEG score recompute
  14. 2026-09-11 14:52 UTCEPSS rescore
  15. 2026-09-11 09:36 UTCEPSS rescore
  16. 2026-09-10 15:46 UTCEG score recompute
  17. 2026-09-10 09:34 UTCEPSS rescore
  18. 2026-09-09 03:50 UTCEG score recompute
  19. 2026-09-08 22:00 UTCEPSS rescore
  20. 2026-09-07 16:13 UTCEG score recompute
  21. 2026-09-07 16:01 UTCEPSS rescore
  22. 2026-09-07 01:08 UTCEG score recompute
  23. 2026-09-06 13:47 UTCEPSS rescore
  24. 2026-09-05 01:24 UTCEG score recompute
  25. 2026-09-04 10:34 UTCEG score recompute
Show 37 more
  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 22:20 UTCEG score recompute
  3. 2026-09-02 14:11 UTCEPSS rescore
  4. 2026-09-01 21:56 UTCEG score recompute
  5. 2026-09-01 13:53 UTCEPSS rescore
  6. 2026-09-01 10:05 UTCEG score recompute
  7. 2026-09-01 04:39 UTCEPSS rescore
  8. 2026-08-30 19:46 UTCEG score recompute
  9. 2026-08-30 19:17 UTCEPSS rescore
  10. 2026-08-30 07:54 UTCEG score recompute
  11. 2026-08-30 01:22 UTCEPSS rescore
  12. 2026-08-29 08:02 UTCEG score recompute
  13. 2026-08-28 21:41 UTCEPSS rescore
  14. 2026-08-27 19:27 UTCEG score recompute
  15. 2026-08-27 14:25 UTCEPSS rescore
  16. 2026-08-26 18:28 UTCEG score recompute
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 18:24 UTCEG score recompute
  19. 2026-08-25 13:48 UTCEPSS rescore
  20. 2026-08-24 18:38 UTCEG score recompute
  21. 2026-08-22 07:19 UTCEG score recompute
  22. 2026-08-21 23:49 UTCEPSS rescore
  23. 2026-08-21 07:35 UTCEG score recompute
  24. 2026-08-20 22:55 UTCEPSS rescore
  25. 2026-08-19 20:00 UTCEG score recompute
  26. 2026-08-19 17:03 UTCEPSS rescore
  27. 2026-08-18 20:15 UTCEG score recompute
  28. 2026-08-18 13:48 UTCEPSS rescore
  29. 2026-08-17 20:30 UTCEG score recompute
  30. 2026-08-17 19:50 UTCEG score recompute
  31. 2026-08-17 13:55 UTCEG score recompute
  32. 2026-08-17 13:47 UTCEPSS rescore
  33. 2026-08-17 02:04 UTCEG score recompute
  34. 2026-08-16 14:56 UTCEPSS rescore
  35. 2026-08-15 14:29 UTCEG score recompute
  36. 2026-08-15 13:28 UTCEG score recompute
  37. 2026-08-15 13:26 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18500?
CVE-2026-18500 is a high vulnerability published on August 15, 2026. @fastify/jwt is a JSON Web Token plugin for Fastify. In versions before 10.2.2, a per-request verification key passed to request.jwtVerify({ key }) is silently overridden by the plugin's globally configured secret, because the option merge applies the global key last. Applications that use…
When was CVE-2026-18500 disclosed?
CVE-2026-18500 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on September 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18500 actively exploited?
CVE-2026-18500 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 94.9% of all scored CVEs.
What is the CVSS score of CVE-2026-18500?
CVE-2026-18500 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-18500?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18500, 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.

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