Model Context Protocol TypeScript SDK: HTTP client transports and OAuth requests followed cross-origin redirects and re-sent custom…
- Exploited
- No known exploitation
- Fix
- Fixed in typescript-sdk 1.32.0 · sdk 1.32.0 · client 2.3.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: typescript-sdk 1.32.0 · sdk 1.32.0 · client 2.3.0.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 24/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Model Context Protocol TypeScript SDK's HTTP client transports and OAuth client requests can leak custom headers, session identifiers, request bodies, and OAuth tokens or client secrets to a different origin when a server responds with a cross-origin redirect. A malicious or compromised MCP or authorization server can trigger this remotely, without logging in, by sending such a redirect, and the bug needs no user action.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.5/10CVSS 6.5
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: typescript-sdk 1.32.0 · sdk 1.32.0 · client 2.3.0.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- modelcontextprotocol typescript-sdk
fixed in 1.32.0
- @modelcontextprotocol sdk
fixed in 1.32.0
- @modelcontextprotocol client
From 2.0.0 · fixed in 2.3.0
Evidence 7
- Advisory
- Repository
- Repository
- Repository
- Repository
Show all 7 sourcesShow fewer sources
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-111769
Is CVE-2026-111769 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-111769?
typescript-sdk: before 1.32.0. sdk: before 1.32.0. client: from 2.0.0 before 2.3.0.Source: cve.now feed data
How do I fix CVE-2026-111769?
Upgrade to a fixed version: typescript-sdk 1.32.0 · sdk 1.32.0 · client 2.3.0.Source: cve.now feed data