Security readout for executives and security teams
Plain-English summary
Older Microsoft Playwright MCP Server releases could accept browser-driven requests without validating the Origin header. A malicious website could use DNS rebinding to reach a victim’s local MCP server and trigger MCP tool endpoints without authorization.
Executive priority
Treat as high priority for developer security. The likely blast radius depends on what MCP tools can do in affected environments, especially file, browser, or automation actions.
Technical view
Versions before 0.0.40 fail to validate Origin on incoming connections. With user browser interaction, DNS rebinding can target a locally running MCP server and cause unintended invocation of tool endpoints. CVSS v4.0 score is 7.2 high.
Likely exposure
Primarily developer workstations, test systems, or automation environments running Microsoft Playwright MCP Server before 0.0.40 locally while users browse attacker-controlled content.
Exploitation context
The bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires a victim browser and a locally running vulnerable MCP server reachable through DNS rebinding.
Researcher notes
Focus validation on local MCP server exposure and version state. Avoid assuming internet-facing exposure; the described path is browser-mediated DNS rebinding against a local service. Exploit evidence is not established in the provided sources.
Mitigation direction
- Upgrade Microsoft Playwright MCP Server to 0.0.40 or later.
- Review the GitHub advisory and patch commit for vendor guidance.
- Stop local MCP server instances when not actively needed.
- Prioritize environments where MCP tools can affect files, browsers, credentials, or automation workflows.
Validation and detection
- Inventory Playwright MCP Server versions across developer and CI environments.
- Confirm no running instances are below version 0.0.40.
- Verify deployed builds include the Origin validation patch.
- Review local MCP activity for unexpected tool endpoint invocations.
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-749: 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 lookupCVE-2025-9611 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
- 7.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L
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
1 official scoreWe 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:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
7.2HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L
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.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/JLLeitschuh/security-research/security/advisories/GHSA-8rgw-6xp9-2fg3CVE reference, VulnCheck · vendor-advisory
- https://github.com/microsoft/playwright/commit/1313fbdCVE reference, VulnCheck · patch
- https://www.vulncheck.com/advisories/microsoft-playwright-mcp-server-dns-rebinding-via-missing-origin-header-validationCVE reference, VulnCheck · third-party-advisory
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.
Exposed Dangerous Method or Function
Exposed Dangerous Method or Function represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.