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Response snapshot Oct 29, 2026, 18:26 UTC

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VulnerabilityCVE-2026-62264

@sylphx/pdf-reader-mcp: HTTP transport accepts unauthenticated requests despite a configured MCP_API_KEY

When @sylphx/pdf-reader-mcp is run as an HTTP server (MCP_TRANSPORT=http), it reads the MCP_API_KEY environment variable and logs API key authentication enabled (X-API-Key header) at startup, but it never validated the X-API-Key header on incoming requests.

At a glance

Exploited
Not known
Severity
7.5 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: @sylphx/pdf-reader-mcp: 3.0.1. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-q344-5v34-gm84 (opens a new tab)

What happened

Impact

When @sylphx/pdf-reader-mcp is run as an HTTP server (MCP_TRANSPORT=http), it reads the MCP_API_KEY environment variable and logs API key authentication enabled (X-API-Key header) at startup, but it never validated the X-API-Key header on incoming requests. The key was read into a variable and never enforced on the request path.

As a result, the /mcp endpoint accepted unauthenticated requests. Combined with the default bind address of 0.0.0.0 (all interfaces), any client able to reach the port could invoke every PDF tool and read the contents of any PDF the server process could open anywhere on the host. URL-based sources also enable limited SSRF (private/loopback addresses are blocked by default unless --allow-private-ips is set).

The misleading startup log made the exposure silent: an operator who set MCP_API_KEY reasonably believed the server was protected when it was not.

Continue reading

This affects only the opt-in HTTP transport; the default stdio transport is unaffected.

Patches

Fixed in @sylphx/pdf-reader-mcp@3.0.1. The fix enforces the X-API-Key header with a constant-time comparison (rejecting missing/mismatched keys with HTTP 401), changes the default bind host to 127.0.0.1 (loopback), and emits a startup warning when binding a non-loopback host without an API key.

Workarounds

For deployments that cannot upgrade immediately:

- Bind to loopback only: MCP_HTTP_HOST=127.0.0.1. - Place a reverse proxy in front that enforces authentication. - Use the default stdio transport instead of HTTP. - Restrict filesystem reach with --allow-dir / MCP_PDF_ALLOWED_DIRS.

Reported privately by novice-22 via responsible disclosure.

Affected package ranges reported by GitHub: @sylphx/pdf-reader-mcp: >= 2.2.0, < 3.0.1

Scores and how they were measured

CVSS base severity

7.5

Version 3.1As of

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

Measurement source (opens a new tab)

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

EPSS probability

Not available

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-q344-5v34-gm84 (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-q344-5v34-gm84, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

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

APA

KEVWire. (2026, October 29). @sylphx/pdf-reader-mcp: HTTP transport accepts unauthenticated requests despite a configured MCP_API_KEY (CVE-2026-62264). https://kevwire.com/record/CVE-2026-62264

MLA

"@sylphx/pdf-reader-mcp: HTTP transport accepts unauthenticated requests despite a configured MCP_API_KEY (CVE-2026-62264)." KEVWire, 29 Oct. 2026, kevwire.com/record/CVE-2026-62264.

Chicago

KEVWire. "@sylphx/pdf-reader-mcp: HTTP transport accepts unauthenticated requests despite a configured MCP_API_KEY (CVE-2026-62264)." Last modified October 29, 2026. https://kevwire.com/record/CVE-2026-62264.

Evidence summary (plain text)

@sylphx/pdf-reader-mcp: HTTP transport accepts unauthenticated requests despite a configured MCP_API_KEY (Oct 29, 2026).
When @sylphx/pdf-reader-mcp is run as an HTTP server (MCP_TRANSPORT=http), it reads the MCP_API_KEY environment variable and logs API key authentication enabled (X-API-Key header) at startup, but it never validated the X-API-Key header on incoming requests. The key was read into a variable and never enforced on the request path.

As a result, the /mcp endpoint accepted unauthenticated requests.
CVSS 7.5 (version 3.1; evidence as of Oct 29, 2026; https://github.com/advisories/GHSA-q344-5v34-gm84).
Sources:
GitHub-reviewed advisory GHSA-q344-5v34-gm84: https://github.com/advisories/GHSA-q344-5v34-gm84
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-62264.
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 29, 2026, 18:26 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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