Mercurius: Incorrect Content-Type parsing can lead to CSRF attack
Published Mar 5, 2026
5.4
MEDIUMCVSS 3.1
EPSS 0.17%
Description
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.
Affected products
-
- Version < 16.4.0StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Mercurius-JS | Mercurius | n/a |
|
- < 16.4.0
No data.
No Red Hat product state for this CVE.
mercurius
npm
Introduced 0 Fixed 16.4.0
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | mercurius | 0 | 16.4.0 |
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
PoCAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed Mar 5, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Mar–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.17% (0.00165) | 5.19th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.16% (0.00159) | 5.41th | v5 (v2026.06.15) |
| Mar 6, 2026 | 0.01% (0.00005) | 0.21th | v4 (v2025.03.14) |
References (5)
- https://github.com/advisories/GHSA-v66j-6wwf-jc57 Advisory
- https://github.com/mercurius-js/mercurius/commit/962d402ec7a92342f4a1b7f5f04af01776838c3c x_refsource_MISCPatch
- https://github.com/mercurius-js/mercurius/pull/1187 x_refsource_MISCIssue TrackingPatch
- https://github.com/mercurius-js/mercurius/security/advisories/GHSA-v66j-6wwf-jc57 exploitx_refsource_CONFIRMPatchVendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2025-64166
| Link | Providers | Tags |
|---|---|---|
| https://github.com/advisories/GHSA-v66j-6wwf-jc57 | Advisory | |
| https://github.com/mercurius-js/mercurius/commit/962d402ec7a92342f4a1b7f5f04af01776838c3c | x_refsource_MISCPatch | |
| https://github.com/mercurius-js/mercurius/pull/1187 | x_refsource_MISCIssue TrackingPatch | |
| https://github.com/mercurius-js/mercurius/security/advisories/GHSA-v66j-6wwf-jc57 | exploitx_refsource_CONFIRMPatchVendor Advisory | |
| https://nvd.nist.gov/vuln/detail/CVE-2025-64166 |
Change history (0)
No recorded changes yet.