CVE-2025-64166

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 94% 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
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

Mercurius is a GraphQL adapter for Fastify. Prior to version 16.4.0, a cross-site request forgery (CSRF) vulnerability was identified. The issue arises from incorrect parsing of the Content-Type header in requests. Specifically, requests with Content-Type values such as application/x-www-form-urlencoded, multipart/form-data, or text/plain could be misinterpreted as application/json. This misinterpretation bypasses the preflight checks performed by the fetch() API, potentially allowing unauthorized actions to be performed on behalf of an authenticated user. This issue has been patched in version 16.4.0.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

March 5, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github.
github Patch Available🟡 PoC Available

Incorrect Content-Type parsing can lead to CSRF attack · Advisory · mercurius-js/mercurius · GitHub

https://github.com/mercurius-js/mercurius/security/advisories/GHSA-v66j-6wwf-jc57
github_pr Patch Available

feat: csrf prevention

Patch available: mercurius-js/mercurius v16.5.0 (PR #1187 merged 2025-09-30)

https://github.com/mercurius-js/mercurius/pull/1187
github_commit Patch Available

commit 962d402ec7a9 (mercurius-js/mercurius)

Patch available: mercurius-js/mercurius v16.5.0 (contains commit 962d402ec7a9)

https://github.com/mercurius-js/mercurius/commit/962d402ec7a92342f4a1b7f5f04af01776838c3c

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
mercurius—16.4.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 25× 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. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-17 19:30 UTCEPSS rescore
  3. 2026-09-16 14:07 UTCEPSS rescore
  4. 2026-09-15 03:10 UTCEPSS rescore
  5. 2026-09-13 16:46 UTCEPSS rescore
  6. 2026-09-12 15:00 UTCEPSS rescore
  7. 2026-09-11 14:52 UTCEPSS rescore
  8. 2026-09-11 09:36 UTCEPSS rescore
  9. 2026-09-10 09:34 UTCEPSS rescore
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-07 16:00 UTCEPSS rescore
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-04 05:06 UTCEPSS rescore
  14. 2026-09-03 00:00 UTCOSV refresh
  15. 2026-09-02 14:11 UTCEPSS rescore
  16. 2026-09-01 13:53 UTCEPSS rescore
  17. 2026-08-30 19:16 UTCEPSS rescore
  18. 2026-08-30 01:21 UTCEPSS rescore
  19. 2026-08-28 21:40 UTCEPSS rescore
  20. 2026-08-27 14:24 UTCEPSS rescore
  21. 2026-08-26 14:45 UTCEPSS rescore
  22. 2026-08-25 13:48 UTCEPSS rescore
  23. 2026-08-24 14:16 UTCEPSS rescore
  24. 2026-08-21 23:48 UTCEPSS rescore
  25. 2026-08-20 22:55 UTCEPSS rescore
Show 37 more
  1. 2026-08-19 17:03 UTCEPSS rescore
  2. 2026-08-17 13:46 UTCEPSS rescore
  3. 2026-08-16 14:55 UTCEPSS rescore
  4. 2026-08-16 12:26 UTCEG score recompute
  5. 2026-08-16 02:13 UTCEPSS rescore
  6. 2026-08-15 01:30 UTCEPSS rescore
  7. 2026-08-15 01:29 UTCEPSS rescore
  8. 2026-08-14 08:23 UTCEG score recompute
  9. 2026-08-13 21:59 UTCEPSS rescore
  10. 2026-08-12 23:59 UTCEG score recompute
  11. 2026-08-12 13:50 UTCEPSS rescore
  12. 2026-08-11 13:42 UTCEPSS rescore
  13. 2026-08-11 05:30 UTCEG score recompute
  14. 2026-08-10 23:59 UTCEPSS rescore
  15. 2026-08-10 07:29 UTCEG score recompute
  16. 2026-08-09 13:46 UTCEPSS rescore
  17. 2026-08-09 13:46 UTCEPSS rescore
  18. 2026-08-09 08:02 UTCEG score recompute
  19. 2026-08-08 16:36 UTCEPSS rescore
  20. 2026-08-07 19:43 UTCEG score recompute
  21. 2026-08-07 16:26 UTCEPSS rescore
  22. 2026-08-06 13:46 UTCEPSS rescore
  23. 2026-08-06 02:32 UTCEG score recompute
  24. 2026-08-05 19:17 UTCEPSS rescore
  25. 2026-08-05 19:17 UTCEPSS rescore
  26. 2026-08-04 15:09 UTCEPSS rescore
  27. 2026-08-04 10:37 UTCEPSS rescore
  28. 2026-08-04 02:12 UTCEG score recompute
  29. 2026-08-03 10:35 UTCEPSS rescore
  30. 2026-08-02 18:43 UTCEG score recompute
  31. 2026-08-02 02:26 UTCEPSS rescore
  32. 2026-08-01 04:15 UTCEPSS rescore
  33. 2026-07-30 16:27 UTCEPSS rescore
  34. 2026-07-30 01:30 UTCEPSS rescore
  35. 2026-07-28 15:35 UTCEPSS rescore
  36. 2026-07-27 14:12 UTCEPSS rescore
  37. 2026-07-27 13:51 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2025-64166?
CVE-2025-64166 is a medium vulnerability published on March 5, 2026. Mercurius is a GraphQL adapter for Fastify. Prior to version 16.4.0, a cross-site request forgery (CSRF) vulnerability was identified. The issue arises from incorrect parsing of the Content-Type header in requests. Specifically, requests with Content-Type values such as…
When was CVE-2025-64166 disclosed?
CVE-2025-64166 was first published in the National Vulnerability Database on March 5, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-64166 actively exploited?
CVE-2025-64166 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 94.5% of all scored CVEs.
What is the CVSS score of CVE-2025-64166?
CVE-2025-64166 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2025-64166?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-64166, 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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