CVE-2026-118661

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 6.5 from GitHub Security Advisory (severity: MODERATE) published 2026-10-28. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Elevated

Also known asEUVD-2026-112468 (ENISA EUVD) · GHSA-5fpq-26gf-qwcr (GitHub Security Advisories)Source: ENISA EUVD

6.5EG
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).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 20.14.6, Happy DOM's CookieContainer in src/cookie/CookieContainer.ts does not correctly validate or match Domain cookie attributes. It can accept a Domain unrelated to the origin setting the cookie, including a public suffix, and separately treats an unrelated suffix-sharing hostname as a match because cookieMatchesURL does not enforce a DNS-label boundary. In server-side rendering and prerendering applications that contact attacker-controlled origins and then make requests to a victim origin, these behaviors can plant and deliver a forged cookie, enabling cookie injection or session fixation. This issue is fixed in version 20.14.6.

CVSS v3
6.5
EG Score
6.5MEDIUMhigh confidence
EG Risk
60
EG Risk 60/100

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)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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 public PoC (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
0.3%
EPSS %ILE
19th
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 (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-02). 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 public PoC (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 28, 2026

Last Modified

November 3, 2026

Advisory Details (4)

Auto-updated Nov 3, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

v20.14.6

Patch available: capricorn86/happy-dom v20.14.6

https://github.com/capricorn86/happy-dom/releases/tag/v20.14.6
GitHub commit Patch Available

commit f21dbd7d0a0c (capricorn86/happy-dom)

Patch available: capricorn86/happy-dom v20.14.6 (contains commit f21dbd7d0a0c)

https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05def4e0f2b3
GitHub pull request Patch Available

fix: Fixes cookie scope forgery vulnerability

Patch available: capricorn86/happy-dom v20.14.6 (PR #2477 merged 2026-10-08)

https://github.com/capricorn86/happy-dom/pull/2477
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies · Advisory · capricorn86/happy-dom · GitHub

https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr

Vendor Advisories for CVE-2026-118661(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
npmhappy-dom @ 20.14.6 (fixes <= 20.14.5)—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

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
happy-dom—
  • every version up to 20.14.6: fixed in 20.14.6
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 21× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  3. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  4. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  5. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  6. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  7. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  8. 2026-11-06 16:36 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  9. 2026-11-05 16:36 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  10. 2026-11-04 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  11. 2026-11-03 16:46 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  12. 2026-11-03 14:29 UTCEchelonGraph re-scored
  13. 2026-11-03 14:29 UTCGHSA enrichmentGHSA-5fpq-26gf-qwcr · GitHub severity MODERATE · GitHub CVSS 6.5
  14. 2026-11-03 13:43 UTCEchelonGraph re-scored
  15. 2026-11-03 13:43 UTCGHSA enrichmentGHSA-5fpq-26gf-qwcr · GitHub severity MODERATE · GitHub CVSS 6.5
  16. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  18. 2026-11-01 07:59 UTCGHSA enrichmentGHSA-5fpq-26gf-qwcr · GitHub severity MODERATE · GitHub CVSS 6.5
  19. 2026-11-01 07:59 UTCEchelonGraph re-scored
  20. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  21. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  22. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  23. 2026-10-28 21:28 UTCEchelonGraph re-scored
  24. 2026-10-28 21:01 UTCENISA EUVD ID recordedEUVD-2026-112468 · Source: ENISA EUVD
  25. 2026-10-28 20:39 UTCEchelonGraph re-scoredFirst assessed: 6.5 MEDIUM
Show 1 more
  1. 2026-10-28 20:38 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-118661?
CVE-2026-118661 is a medium-severity vulnerability; its CVE record was published on October 28, 2026. Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 20.14.6, Happy DOM's CookieContainer in src/cookie/CookieContainer.ts does not correctly validate or match Domain cookie attributes. It can accept a Domain unrelated to the origin setting the…
When was the CVE record for CVE-2026-118661 published?
The CVE record for CVE-2026-118661 was published on October 28, 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 November 3, 2026; the record at its source may have been updated since.
Is CVE-2026-118661 actively exploited?
CVE-2026-118661 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (19th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-118661?
CVE-2026-118661 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-118661?
A fix for CVE-2026-118661 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-118661 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-2026-118661

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