cve.bz

CVE-2026-111769

6.5 mediumEPSS 0.4%Fix available

Medium (6.5). EPSS 0.4% estimated probability of exploitation activity in the next 30 days. Fixed in @modelcontextprotocol/sdk 1.32.0.

On this page
The Model Context Protocol TypeScript SDK provides TypeScript client and server implementations of the Model Context Protocol. Prior to 1.32.0 in @modelcontextprotocol/sdk and from 2.0.0 until 2.3.0 in @modelcontextprotocol/client, the HTTP client transports and OAuth client requests followed redirects to a different origin while retaining custom request headers and, for HTTP 307 or 308 responses, request bodies. The affected surfaces are StreamableHTTPClientTransport, SSEClientTransport, and OAuth client functions such as auth(). The trigger is an HTTP redirect to another origin. Custom headers and mcp-session-id can be re-sent to the redirected origin. HTTP 307 and 308 redirects can also re-send the request body. OAuth request bodies can contain refresh_token and client_secret values. Current runtimes already strip the Authorization header across origins. stdio clients do not use the affected HTTP path. A malicious or compromised MCP or authorization server could therefore receive API keys, session identifiers, OAuth refresh tokens, or OAuth client secrets. Restoring unrestricted redirect following after upgrading restores the exposure. This issue is fixed in @modelcontextprotocol/sdk 1.32.0 and @modelcontextprotocol/client 2.3.0.

Severity

CVSS 3.1

6.5 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
EPSS
0.4% estimated probability of exploitation activity in the next 30 days; 35th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-09. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
OWASP Top 10
A01:2025 Broken Access Control
Published
Modified
NVD analysis
Awaiting analysis
Record from
the NVD, synced

Ask an AI about this CVE

ChatGPTClaudeGoogle AI Mode

Show the promptExplain CVE-2026-111769 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-111769?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-111769?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-111769 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.

Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.

Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
modelcontextprotocol typescript-sdk< 1.32.0
@modelcontextprotocol sdk< 1.32.0
@modelcontextprotocol client>= 2.0.0, < 2.3.0

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-6prh-2h8m-c8cwnpm@modelcontextprotocol/sdk<1.32.01.32.0
GHSA-6prh-2h8m-c8cwnpm@modelcontextprotocol/client>=2.0.0 <2.3.02.3.0

Attack patterns (CAPEC)

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-200 (59).

References

Check your stackJSON