CVE-2026-34226

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 62% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions prior to 20.8.9 may attach cookies from the current page origin (window.location) instead of the request target URL when fetch(..., { credentials: "include" }) is used. This can leak cookies from origin A to destination B. Version 20.8.9 fixes the issue.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
EPSS PROB
0.6%
EPSS %ILE
46th
KEV
Not listed

Published

March 27, 2026

Last Modified

August 19, 2026

Advisory Details (8)

Auto-updated Jul 6, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github_release, github, redhat.
redhat
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34226.json
redhat

2452519 – (CVE-2026-34226) CVE-2026-34226 happy-dom: Happy DOM: Information disclosure via incorrect cookie handling in fetch requests

https://bugzilla.redhat.com/show_bug.cgi?id=2452519
redhatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-34226
githubMentions a patch (unverified)🟡 PoC Available

fetch credentials include uses page-origin cookies instead of target-origin cookies · Advisory · capricorn86/happy-dom · GitHub

https://github.com/capricorn86/happy-dom/security/advisories/GHSA-w4gp-fjgq-3q4g
github_release Patch Available

v20.8.9

Patch available: capricorn86/happy-dom v20.8.9

https://github.com/capricorn86/happy-dom/releases/tag/v20.8.9
github_pr Patch Available

fix: [#0] Fixes issue where cookies from the current origin was being forwarded to the target origin in fetch requests

Patch available: capricorn86/happy-dom v20.8.9 (PR #2117 merged 2026-03-26)

https://github.com/capricorn86/happy-dom/pull/2117
github_commit Patch Available

commit 68324c21d7b9 (capricorn86/happy-dom)

Patch available: capricorn86/happy-dom v20.8.9 (contains commit 68324c21d7b9)

https://github.com/capricorn86/happy-dom/commit/68324c21d7b98f53f7bb5a7b3e185bda7106e751
generic

happy-dom/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts at f8d8cad41e9722fab9eefb9dfb3cca696462e908 · capricorn86/happy-dom · GitHub

https://github.com/capricorn86/happy-dom/blob/f8d8cad41e9722fab9eefb9dfb3cca696462e908/packages/happy-dom/src/fetch/utilities/FetchRequestHeaderUtility.ts

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
happy-dom—
  • every version up to 20.8.9: fixed in 20.8.9
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 24× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 116 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:47 UTCEPSS rescore
  4. 2026-10-06 15:17 UTCEPSS rescore
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  11. 2026-09-27 13:48 UTCEPSS rescore
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  14. 2026-09-25 14:15 UTCOSV refresh
  15. 2026-09-18 19:28 UTCEPSS rescore
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  1. 2026-09-08 22:00 UTCEPSS rescore
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  3. 2026-09-06 13:47 UTCEPSS rescore
  4. 2026-09-06 05:22 UTCOSV refresh
  5. 2026-09-04 05:06 UTCEPSS rescore
  6. 2026-09-02 14:12 UTCEPSS rescore
  7. 2026-09-01 13:53 UTCEPSS rescore
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  9. 2026-08-30 19:17 UTCEPSS rescore
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  21. 2026-08-19 16:12 UTCEG score recompute
  22. 2026-08-18 13:48 UTCEPSS rescore
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  25. 2026-08-16 09:55 UTCEG score recompute
  26. 2026-08-16 02:14 UTCEPSS rescore
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  28. 2026-08-14 06:14 UTCEG score recompute
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  30. 2026-08-12 20:33 UTCEG score recompute
  31. 2026-08-12 13:50 UTCEPSS rescore
  32. 2026-08-11 20:43 UTCEG score recompute
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  35. 2026-08-09 16:54 UTCEG score recompute
  36. 2026-08-09 13:46 UTCEPSS rescore
  37. 2026-08-09 05:48 UTCEG score recompute
  38. 2026-08-08 16:37 UTCEPSS rescore
  39. 2026-08-08 03:19 UTCEG score recompute
  40. 2026-08-06 18:34 UTCEG score recompute
  41. 2026-08-06 13:46 UTCEPSS rescore
  42. 2026-08-06 00:44 UTCEG score recompute
  43. 2026-08-05 19:17 UTCEPSS rescore
  44. 2026-08-04 15:10 UTCEPSS rescore
  45. 2026-08-04 10:38 UTCEPSS rescore
  46. 2026-08-03 23:05 UTCEG score recompute
  47. 2026-08-03 10:36 UTCEPSS rescore
  48. 2026-08-02 15:08 UTCEG score recompute
  49. 2026-08-02 02:27 UTCEPSS rescore
  50. 2026-08-01 04:16 UTCEPSS rescore
  51. 2026-07-30 16:28 UTCEPSS rescore
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  53. 2026-07-27 14:13 UTCEPSS rescore
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  62. 2026-07-23 03:09 UTCEG score recompute
  63. 2026-07-22 14:08 UTCEPSS rescore
  64. 2026-07-21 15:24 UTCEPSS rescore
  65. 2026-07-20 17:08 UTCEPSS rescore
  66. 2026-07-19 14:31 UTCEPSS rescore
  67. 2026-07-19 02:29 UTCEPSS rescore
  68. 2026-07-18 10:04 UTCEPSS rescore
  69. 2026-07-18 06:59 UTCOSV refresh
  70. 2026-07-16 17:03 UTCEPSS rescore
  71. 2026-07-15 16:57 UTCEPSS rescore
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  73. 2026-07-15 02:00 UTCEPSS rescore
  74. 2026-07-13 22:30 UTCEPSS rescore
  75. 2026-07-13 06:13 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-34226?
CVE-2026-34226 is a high vulnerability published on March 27, 2026. Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Versions prior to 20.8.9 may attach cookies from the current page origin (window.location) instead of the request target URL when fetch(..., { credentials: "include" }) is used. This can leak cookies…
When was CVE-2026-34226 disclosed?
CVE-2026-34226 was first published on March 27, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-34226 actively exploited?
CVE-2026-34226 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (46th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-34226?
CVE-2026-34226 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-34226?
A fix for CVE-2026-34226 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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