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

August 17, 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 / 21× 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. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 18:24 UTCEG score recompute
  3. 2026-08-25 13:48 UTCEPSS rescore
  4. 2026-08-24 18:38 UTCEG score recompute
  5. 2026-08-22 07:19 UTCEG score recompute
  6. 2026-08-21 23:49 UTCEPSS rescore
  7. 2026-08-21 07:35 UTCEG score recompute
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-19 20:00 UTCEG score recompute
  10. 2026-08-19 17:03 UTCEPSS rescore
  11. 2026-08-18 20:15 UTCEG score recompute
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 20:30 UTCEG score recompute
  14. 2026-08-17 19:50 UTCEG score recompute
  15. 2026-08-17 13:55 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 02:04 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-15 14:29 UTCEG score recompute
  20. 2026-08-15 13:28 UTCEG score recompute
  21. 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 August 17, 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 95.1% 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.

Dependency Blast Radius

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