CVE-2026-115895

HIGHPre-NVD 8.88.8
EchelonGraph scoreHIGH confidence

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

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-10-23. A secondary CVSS source baseline 8.8; 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 weekElevated

Also known asEUVD-2026-109189 (ENISA EUVD) · GHSA-834v-8h66-3h79 (GitHub Security Advisories)Source: ENISA EUVD

8.8EG
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: 0.5%CVSS: 8.8Exploit: 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. From 17.0.0 until 21.0.4, packages/happy-dom/src/module/ECMAScriptModuleCompiler.ts accepts a named ESM import alias without validating that it is a JavaScript binding identifier before inserting it into a generated destructuring binding. With enableJavaScriptEvaluation enabled, attacker-controlled HTML or module source can use an invalid alias that becomes a valid default initializer after compilation, causing the generated JavaScript to execute in the Node.js host process. The demonstrated reachable path uses a JSON module import attribute, which prevents the malicious alias from being emitted again in a later ESM circular-import assignment and keeps the generated function syntactically valid. This incomplete fix for CVE-2026-33943 is a distinct residual path because the earlier remediation validated the local export importName path but not the named-import alias. This issue is fixed in version 21.0.4.

CVSS v3
8.8
EG Score
8.8HIGHhigh confidence
EG Risk
56
EG Risk 56/100

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)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.5%
EPSS %ILE
40th
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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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, Track* at medium and Attend at high mission impact.

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 no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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 23, 2026

Last Modified

October 30, 2026

Advisory Details (4)

Auto-updated Oct 23, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

v21.0.4

Patch available: capricorn86/happy-dom v21.0.4

https://github.com/capricorn86/happy-dom/releases/tag/v21.0.4
GitHub commit Patch Available

commit fd163520b74d (capricorn86/happy-dom)

Patch available: capricorn86/happy-dom v21.0.4 (contains commit fd163520b74d)

https://github.com/capricorn86/happy-dom/commit/fd163520b74d9fa146be91f7b4e4f46d6cccbe13
GitHub pull request Patch Available

fix: Fixed a code injection vulnerability in the ESM compiler

Patch available: capricorn86/happy-dom v21.0.4 (PR #2537 merged 2026-10-20)

https://github.com/capricorn86/happy-dom/pull/2537
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Incomplete fix for CVE-2026-33943: unsanitized import alias leads to host code execution · Advisory · capricorn86/happy-dom · GitHub

https://github.com/capricorn86/happy-dom/security/advisories/GHSA-834v-8h66-3h79

Vendor Advisories for CVE-2026-115895(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 @ 21.0.4 (fixes >= 17.0.0, <= 21.0.3)—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—
  • 17.0.0 up to 21.0.4: fixed in 21.0.4
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 18× 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 0.5% · 40th percentile
  2. 2026-11-01 07:59 UTCGHSA enrichmentGHSA-834v-8h66-3h79 · GitHub severity HIGH · GitHub CVSS 8.8
  3. 2026-11-01 07:59 UTCEG score recompute
  4. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-30 19:27 UTCEG score recompute
  6. 2026-10-30 18:50 UTCEG score recompute
  7. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  11. 2026-10-26 18:49 UTCEG score recompute
  12. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  13. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  14. 2026-10-25 14:50 UTCEG score recompute
  15. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  16. 2026-10-23 22:29 UTCEG score recompute
  17. 2026-10-23 21:35 UTCEG score recomputeFirst assessed: 8.8 HIGH
  18. 2026-10-23 21:34 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-115895?
CVE-2026-115895 is a high-severity vulnerability; its CVE record was published on October 23, 2026. Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. From 17.0.0 until 21.0.4, packages/happy-dom/src/module/ECMAScriptModuleCompiler.ts accepts a named ESM import alias without validating that it is a JavaScript binding identifier before inserting it into…
When was the CVE record for CVE-2026-115895 published?
The CVE record for CVE-2026-115895 was published on October 23, 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 30, 2026; the record at its source may have been updated since.
Is CVE-2026-115895 actively exploited?
CVE-2026-115895 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-115895?
CVE-2026-115895 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-115895?
A fix for CVE-2026-115895 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-115895 are linked in the Vendor Advisories panel on this page.

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