Security readout for executives and security teams
Plain-English summary
FastMCP versions before 2.14.2 can issue OAuth tokens for the proxy base URL instead of the specific MCP server requested. In environments with multiple MCP servers, this may let a token intended for one resource be accepted more broadly than intended.
Executive priority
Treat this as a high-priority dependency update for MCP services using OAuth. Business risk is unauthorized cross-resource access, not broad infrastructure takeover based on available evidence.
Technical view
The OAuth Proxy mishandles the OAuth resource parameter during authorization and token requests. Tokens are scoped to the OAuthProxy base_url rather than the requested MCP server resource. The issue affects jlowin/fastmcp versions before 2.14.2 and is fixed in 2.14.2. CVSS v4.0 is 7.4 high.
Likely exposure
Exposure is likely limited to deployments using FastMCP OAuthProxy before 2.14.2, especially where multiple MCP servers or resource identifiers rely on OAuth scoping boundaries.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. CVSS indicates network attack vector, high attack complexity, no privileges, and user interaction required.
Researcher notes
Evidence supports an authorization scoping flaw, mapped to CWE-1220 and CWE-863. The key validation point is whether tokens are issued for base_url instead of the client-supplied resource. No public exploit evidence is included in the bundle.
Mitigation direction
- Upgrade FastMCP to version 2.14.2 or later.
- Prioritize FastMCP deployments that use OAuthProxy.
- Review vendor and Red Hat advisories for downstream package status.
- Reassess OAuth token scoping assumptions after upgrading.
- Check vendor guidance before applying compensating controls.
Validation and detection
- Inventory FastMCP versions in application dependencies and images.
- Confirm no deployed environment uses FastMCP below 2.14.2.
- Identify services initializing OAuthProxy and mapped MCP resources.
- Review authentication design for shared base_url token assumptions.
- Check advisories for any later clarification or affected downstream packages.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1220: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-69196 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.4 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N——GitHub_MCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N2.25.2redhat-SADPVulnerability scoring details
Base CVSS 4.0 score
7.4HighVector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-03-16T19:01:37.622Z: Reported to Red Hat.
- 2026-03-16T18:07:06.332Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-5h2m-4q8j-pqpjCVE reference, GitHub_M · x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2025-69196CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2448179CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-69196.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:36350CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Insufficient Granularity of Access Control
Insufficient Granularity of Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.