CVE-2026-104850

HIGHPre-NVD 7.57.5
EchelonGraph scoreHIGH confidence

“—” 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.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-93491 (ENISA EUVD) · GHSA-6qxp-vccf-f47h (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
49
EG 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, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

2.2.0

Patch available: modelcontextprotocol/typescript-sdk v2.2.0

https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v2.2.0
GitHub commit Patch Available

commit 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/edd12e282620ebf770d67316f19cf91d4112a1bd
GitHub pull request Patch Available

fix(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/2887
GitHub advisoryMentions a patch (unverified)

OAuth 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-f47h

Vendor 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 / EcosystemFix (by version range) / PatchReleasedSource
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)
PackageVulnerable rangeFix by version rangeDependents
@modelcontextprotocol/client—
  • 2.0.0 up to 2.2.0: fixed in 2.2.0
—
@modelcontextprotocol/sdk—
  • 1.12.0 up to 1.31.0: fixed in 1.31.0
—

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.

  1. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  2. 2026-11-01 08:00 UTCGHSA enrichmentGHSA-6qxp-vccf-f47h · GitHub severity HIGH · GitHub CVSS 7.5
  3. 2026-11-01 08:00 UTCEG score recompute
  4. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  5. 2026-10-31 02:46 UTCEG score recompute
  6. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  7. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  8. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  9. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  12. 2026-10-25 14:55 UTCEG score recompute
  13. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  14. 2026-10-24 11:29 UTCEG score recompute
  15. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  16. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  17. 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  18. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  19. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  20. 2026-10-18 05:09 UTCEG score recompute
  21. 2026-10-17 19:39 UTCEG score recompute
  22. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  23. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  24. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  25. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
Show 17 more
  1. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  2. 2026-10-12 16:40 UTCEG score recompute
  3. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  4. 2026-10-11 20:15 UTCEG score recompute
  5. 2026-10-11 18:27 UTCEG score recompute
  6. 2026-10-11 15:01 UTCEG score recompute
  7. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  8. 2026-10-10 22:29 UTCEG score recompute
  9. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  10. 2026-10-09 21:58 UTCEG score recompute
  11. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  12. 2026-10-08 21:27 UTCEG score recompute
  13. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  14. 2026-10-08 09:01 UTCEG score recompute
  15. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  16. 2026-10-06 17:19 UTCEG score recompute
  17. 2026-10-06 15:59 UTCEG score recomputeFirst assessed: 7.5 HIGH

Frequently asked(5)

What is CVE-2026-104850?
CVE-2026-104850 is a high-severity vulnerability; its CVE record was published on October 6, 2026. 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…
When was the CVE record for CVE-2026-104850 published?
The CVE record for CVE-2026-104850 was published on October 6, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 6, 2026; the record at its source may have been updated since.
Is CVE-2026-104850 actively exploited?
CVE-2026-104850 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-104850?
CVE-2026-104850 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-104850?
A fix for CVE-2026-104850 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-104850 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-104850

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