Security readout for executives and security teams
Plain-English summary
FastMCP before 2.14.2 could issue OAuth tokens for the proxy base URL instead of the specific MCP server requested. In multi-server MCP environments, that can let a token intended for one server be accepted in the wrong place. The issue is high severity but requires user interaction and higher attack complexity.
Executive priority
Prioritize remediation for externally reachable or multi-tenant MCP services using FastMCP OAuthProxy. This is not confirmed as exploited, but token scoping failures can undermine access boundaries between MCP servers.
Technical view
The OAuthProxy authorization and token flow did not properly honor the client-supplied resource parameter. Tokens were scoped to the OAuthProxy base_url configured at initialization rather than explicitly to the target MCP server. Sources list FastMCP versions before 2.14.2 as affected and state 2.14.2 patched the issue.
Likely exposure
Exposure is most likely in applications using jlowin/PrefectHQ FastMCP OAuthProxy below 2.14.2, especially deployments proxying authentication across multiple MCP servers. Systems not using FastMCP OAuthProxy are not shown as affected by the provided sources.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. CVSS 4.0 rates it 7.4 with network attack vector, high complexity, no privileges required, and user interaction required. Treat exploitation status as unconfirmed.
Researcher notes
Useful review areas are OAuthProxy resource handling, token audience/resource claims, and multi-server authorization boundaries. The provided evidence identifies the vulnerable behavior and fixed version, but does not include exploit proof, affected CPEs, or detailed patch internals.
Mitigation direction
- Upgrade FastMCP to version 2.14.2 or later.
- Prioritize MCP deployments using OAuthProxy across multiple servers.
- Review PrefectHQ/FastMCP and Red Hat advisories for environment-specific guidance.
- After patching, assess whether previously issued OAuth tokens require revocation.
- Monitor dependency manifests for FastMCP versions below 2.14.2.
Validation and detection
- Check dependency lockfiles and runtime inventories for fastmcp versions below 2.14.2.
- Identify services using FastMCP OAuthProxy rather than unrelated FastMCP features.
- Confirm token audience or resource binding matches the intended MCP server.
- Review authentication logs for unexpected token reuse across MCP server boundaries.
- Track Red Hat advisory RHSA-2026:36350 if using affected Red Hat packaging.
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.