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Response snapshot Oct 27, 2026, 05:12 UTC

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VulnerabilityCVE-2026-111767

MCP TypeScript SDK: Experimental tasks were not tied to the session that created them

Experimental tasks are deprecated. The 2026-07-28 specification replaced them with a redesigned extension. The best course of action is to stop using them. Affected versions: `@modelcontextprotocol/sdk` 1.24.0 through 1.31.0. The 2.x packages are not affected.

At a glance

Exploited
Not known
Severity
8.6 High (CVSS 3.1)
Chance of exploitation
0.3% in the next 30 days
Sources
2 independent sources

What to do

GitHub lists first patched versions: @modelcontextprotocol/sdk: 1.32.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-22jm-h49p-29qw (opens a new tab)

What happened

### Summary In affected versions, the experimental tasks feature (`taskStore`) did not check which session created a task. Clients sharing one `InMemoryTaskStore` could list, read and cancel each other's tasks.

Experimental tasks are deprecated. The 2026-07-28 specification replaced them with a redesigned extension. The best course of action is to stop using them.

### Am I affected? Only if your HTTP server passes `taskStore` to `McpServer` or `Server`. If `grep -ri taskstore --exclude-dir=node_modules .` finds nothing, you are not affected.

Affected versions: `@modelcontextprotocol/sdk` 1.24.0 through 1.31.0. The 2.x packages are not affected.

Continue reading

### Fix Upgrade to `@modelcontextprotocol/sdk` 1.32.0 or later. Each task is now tied to the session that created it, so a client that starts a new session can no longer reach its earlier tasks.

If you cannot upgrade yet, remove `taskStore`, or create one `InMemoryTaskStore` per session.

Affected package ranges reported by GitHub: @modelcontextprotocol/sdk: >= 1.24.0, < 1.32.0

Scores and how they were measured

CVSS base severity

8.6

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.3%

Scored Percentile 27.8%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-22jm-h49p-29qw (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  4. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  5. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  6. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  7. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  8. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  9. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  10. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-22jm-h49p-29qw, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  11. Primary source

    NVD CVE-2026-111767 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  12. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  13. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-111767, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 20). MCP TypeScript SDK: Experimental tasks were not tied to the session that created them (CVE-2026-111767). https://kevwire.com/record/CVE-2026-111767

MLA

"MCP TypeScript SDK: Experimental tasks were not tied to the session that created them (CVE-2026-111767)." KEVWire, 20 Oct. 2026, kevwire.com/record/CVE-2026-111767.

Chicago

KEVWire. "MCP TypeScript SDK: Experimental tasks were not tied to the session that created them (CVE-2026-111767)." Last modified October 20, 2026. https://kevwire.com/record/CVE-2026-111767.

Evidence summary (plain text)

MCP TypeScript SDK: Experimental tasks were not tied to the session that created them (Oct 20, 2026).
Experimental tasks are deprecated. The 2026-07-28 specification replaced them with a redesigned extension. The best course of action is to stop using them.

Affected versions: `@modelcontextprotocol/sdk` 1.24.0 through 1.31.0. The 2.x packages are not affected.
CVSS 8.6 (version 3.1; evidence as of Oct 20, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-111767).
EPSS 0.3% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-111767&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-22jm-h49p-29qw: https://github.com/advisories/GHSA-22jm-h49p-29qw
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQxNDowNjoxNFrOAAfxZw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQwODoyNzoyM1rOAAYp9A%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMTozNTo1OFrOAAfwCQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMTozMDoxM1rOAAfv2A%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMToyODowOVrOAAfv1g%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMToyNDoyMFrOAAfv1Q%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDo0NTowN1rOAAfvzQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDozMDoyNlrOAAfvxw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDowMzo1N1rOAAfvxQ%3D%3D
NVD CVE-2026-111767: https://nvd.nist.gov/vuln/detail/CVE-2026-111767
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?pubStartDate=2026-10-12T13:35:55.142Z&pubEndDate=2026-10-26T13:35:55.142Z&resultsPerPage=500&startIndex=6000
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-111767&date=2026-10-26
Record ID: CVE-2026-111767.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 01:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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