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Response snapshot Oct 29, 2026, 01:26 UTC

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VulnerabilityCVE-2026-118659

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface.

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HTTP/2 requests and resolves attacker-controlled :path values against server.

At a glance

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

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-118659 (opens a new tab)

What happened

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HTTP/2 requests and resolves attacker-controlled :path values against server.targetOrigin in #onIncomingRequest in packages/@happy-dom/server-renderer/src/ServerRendererServer.

ts without confirming that the resolved origin remains trusted before calling fetch. A protocol-relative path can change the destination to an arbitrary HTTP or HTTPS endpoint reachable by the server, including local and internal services, and the proxy relays the fetched response headers and body to the requester. This issue is fixed in version 21.0.2.

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.

Sources

  1. Primary source

    NVD CVE-2026-118659 (opens a new tab)

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

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    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 28). Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. (CVE-2026-118659). https://kevwire.com/record/CVE-2026-118659

MLA

"Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. (CVE-2026-118659)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2026-118659.

Chicago

KEVWire. "Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. (CVE-2026-118659)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2026-118659.

Evidence summary (plain text)

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. (Oct 28, 2026).
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HTTP/2 requests and resolves attacker-controlled :path values against server.targetOrigin in #onIncomingRequest in packages/@happy-dom/server-renderer/src/ServerRendererServer.ts without confirming that the resolved origin remains trusted before calling fetch.
CVSS 7.5 (version 3.1; evidence as of Oct 28, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-118659).
Sources:
NVD CVE-2026-118659: https://nvd.nist.gov/vuln/detail/CVE-2026-118659
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T21:10:57.957Z&lastModEndDate=2026-10-28T22:40:57.609Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T20:41:00.896Z&lastModEndDate=2026-10-28T22:10:55.656Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T20:10:59.549Z&lastModEndDate=2026-10-28T21:40:57.581Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-118659.
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 28, 2026, 22:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

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.

Record JSON

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Record details

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