MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. Starting in version 1.12.0 and prior to versions 1.31.0 and 2.2.0, the SDK's OAuth client support let the MCP server a client connected to decide which authorization server received the client's OAuth credentials. Stored and pre-provisioned credentials were not bound to the authorization server they belong to. A malicious or compromised MCP server could name its own authorization server in its protected resource metadata. Without any user interaction, the client would send that server the refresh_token and client_secret stored from an earlier sign-in (1.x), or the configured client_secret or signed assertion of a bundled non-interactive provider (1.x and 2.x). Only those applications that use the SDK as an MCP client over HTTP with an authProvider: your own OAuthClientProvider, or the bundled ClientCredentialsProvider, PrivateKeyJwtProvider, StaticPrivateKeyJwtProvider or (2.x) CrossAppAccessProvider and that may connect to an MCP server the owners does not fully trust while holding credentials for a legitimate authorization server are affected. @modelcontextprotocol/sdk 1.31.0 (1.x) and @modelcontextprotocol/client 2.2.0 (2.x) patch the issue. A workaround for those who cannot upgrade is available. 2.0.0 and 2.1.0 already accept expectedIssuer. On 1.x, the only workaround is to connect OAuth-enabled clients only to MCP servers you trust.
CVE-2026-104850
“—” beside the score: it is equal to the CVSS score beside it.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-06. A secondary CVSS source baseline 7.5; sources differ by 0.0.
Also known asEUVD-2026-93491 (ENISA EUVD) · GHSA-6qxp-vccf-f47h (GitHub Security Advisories)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHhigh confidence
- EG Risk
- 49EG Risk 49/100
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)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.2% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.2%
- EPSS %ILE
- 13th
- 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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 6, 2026
Last Modified
October 6, 2026
Advisory Details (4)
Auto-updated Oct 6, 20262.2.0
Patch available: modelcontextprotocol/typescript-sdk v2.2.0
https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v2.2.0commit edd12e282620 (modelcontextprotocol/typescript-sdk)
Patch available: modelcontextprotocol/typescript-sdk @modelcontextprotocol/server-legacy@2.2.0 (contains commit edd12e282620)
https://github.com/modelcontextprotocol/typescript-sdk/commit/edd12e282620ebf770d67316f19cf91d4112a1bdfix(client): deprecate omitting expectedIssuer and apply the SEP-2352 issuer check consistently
Patch available: modelcontextprotocol/typescript-sdk @modelcontextprotocol/server-legacy@2.2.0 (PR #2887 merged 2026-09-28)
https://github.com/modelcontextprotocol/typescript-sdk/pull/2887OAuth client could send credentials to an authorization server chosen by the MCP server · Advisory · modelcontextprotocol/typescript-sdk · GitHub
https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-6qxp-vccf-f47hVendor Advisories for CVE-2026-104850(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 @ 2.2.0 (fixes >= 2.0.0, < 2.2.0) | — | ghsa |
| npm | @modelcontextprotocol/sdk @ 1.31.0 (fixes >= 1.12.0, < 1.31.0) | — | 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(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 42× 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 it from the CNA feed. 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). Most recent first.
- 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-11-01 08:00 UTCGHSA enrichmentGHSA-6qxp-vccf-f47h · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-11-01 08:00 UTCEG score recompute
- 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-31 02:46 UTCEG score recompute
- 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
- 2026-10-25 14:55 UTCEG score recompute
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-24 11:29 UTCEG score recompute
- 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-18 05:09 UTCEG score recompute
- 2026-10-17 19:39 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
Show 17 moreShow fewer
- 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-12 16:40 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-11 20:15 UTCEG score recompute
- 2026-10-11 18:27 UTCEG score recompute
- 2026-10-11 15:01 UTCEG score recompute
- 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-10 22:29 UTCEG score recompute
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-09 21:58 UTCEG score recompute
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-08 21:27 UTCEG score recompute
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-08 09:01 UTCEG score recompute
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
- 2026-10-06 17:19 UTCEG score recompute
- 2026-10-06 15:59 UTCEG score recomputeFirst assessed: 7.5 HIGH
Related CVEs(same product + same CWE)
Same product
4 shownnpm:@modelcontextprotocol/sdk
Same CWE
10 shownCWE-522 · CWE-345
Frequently asked(5)
What is CVE-2026-104850?
When was the CVE record for CVE-2026-104850 published?
Is CVE-2026-104850 actively exploited?
What is the CVSS score of CVE-2026-104850?
How do I remediate CVE-2026-104850?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-104850
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