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-2026-111769
“—” beside the score: it is equal to the CVSS score beside it.
Score 6.5 from GitHub Security Advisory (severity: MODERATE) published 2026-10-20. A secondary CVSS source baseline 6.5; sources differ by 0.0.
Also known asEUVD-2026-117802 (ENISA EUVD) · GHSA-6prh-2h8m-c8cw (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5MEDIUMhigh confidence
- EG Risk
- 29EG Risk 29/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity65% × 45%Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.4% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.4%
- EPSS %ILE
- 35th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 20, 2026
Last Modified
November 12, 2026
Advisory Details (6)
Auto-updated Nov 5, 2026HTTP client transports and OAuth requests followed cross-origin redirects and re-sent custom headers and request bodies · Advisory · modelcontextprotocol/typescript-sdk · GitHub
https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-6prh-2h8m-c8cw1.32.0
Patch available: modelcontextprotocol/typescript-sdk 1.32.0
https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/1.32.0[v1.x] fix(client): follow redirects only within the endpoint's origin
Patch available: modelcontextprotocol/typescript-sdk 1.32.0 (PR #2902 merged 2026-09-30)
https://github.com/modelcontextprotocol/typescript-sdk/pull/2902fix(client): follow redirects only within the origin of the request
Patch available: modelcontextprotocol/typescript-sdk @modelcontextprotocol/[email protected] (PR #2901 merged 2026-09-30)
https://github.com/modelcontextprotocol/typescript-sdk/pull/2901commit 433eb413dc30 (modelcontextprotocol/typescript-sdk)
Patch available: modelcontextprotocol/typescript-sdk @modelcontextprotocol/[email protected] (contains commit 433eb413dc30)
https://github.com/modelcontextprotocol/typescript-sdk/commit/433eb413dc305ebeb93b8ebcde0095a8fc0d5fa0commit 30bfe5139f4b (modelcontextprotocol/typescript-sdk)
Patch available: modelcontextprotocol/typescript-sdk 1.32.0 (contains commit 30bfe5139f4b)
https://github.com/modelcontextprotocol/typescript-sdk/commit/30bfe5139f4b0825c90cd725f9a7e3f9af5e120dVendor Advisories for CVE-2026-111769(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(2)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| npm | @modelcontextprotocol/client @ 2.3.0 (fixes >= 2.0.0, < 2.3.0) | — | ghsa |
| npm | @modelcontextprotocol/sdk @ 1.32.0 (fixes < 1.32.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(2 across 1 ecosystem)
npm(2)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| @modelcontextprotocol/client | — |
| — |
| @modelcontextprotocol/sdk | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 15× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-11-12 22:30 UTCEchelonGraph re-scored
- 2026-11-12 22:30 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-11-09 19:27 UTCEchelonGraph re-scored
- 2026-11-09 19:27 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-09 18:50 UTCEchelonGraph re-scored
- 2026-11-09 18:50 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
- 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.4% · 34th percentile
- 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.4% · 34th percentile
- 2026-11-06 16:36 UTCEPSS rescoreEPSS 0.4% · 34th percentile
- 2026-11-05 22:29 UTCEchelonGraph re-scored
- 2026-11-05 22:29 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-05 22:12 UTCENISA EUVD ID recordedEUVD-2026-117802 · Source: ENISA EUVD
- 2026-11-05 21:28 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-01 07:59 UTCGHSA enrichmentGHSA-6prh-2h8m-c8cw · GitHub severity MODERATE · GitHub CVSS 6.5
- 2026-11-01 07:59 UTCEchelonGraph re-scored
- 2026-10-25 14:52 UTCEchelonGraph re-scored
- 2026-10-20 19:21 UTCEchelonGraph re-scoredFirst assessed: 6.5 MEDIUM
Related CVEs(same product + same CWE)
Same product
7 shownnpm:@modelcontextprotocol/client · npm:@modelcontextprotocol/sdk
Frequently asked(5)
What is CVE-2026-111769?
When was the CVE record for CVE-2026-111769 published?
Is CVE-2026-111769 actively exploited?
What is the CVSS score of CVE-2026-111769?
How do I remediate CVE-2026-111769?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-111769
Is Your Infrastructure Affected by CVE-2026-111769?
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