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CVE-2026-33943

39
FAUCET Score

CVE-2026-33943 details a high-severity code injection vulnerability in Happy DOM, a JavaScript web browser implementation, affecting versions 15.10.0 through 20.8.7. This flaw in the ECMAScriptModuleCompiler allows an attacker to achieve Remote Code Execution (RCE) by injecting unsanitized JavaScript expressions within ES module `export { }` declarations. Rated 8.8 HIGH on the CVSS scale, the vulnerability requires user interaction but can be exploited over the network with low attack complexity, leading to high impact on confidentiality, integrity, and availability. There is currently no evidence of active exploitation, nor are public exploit modules available on platforms like Metasploit or ExploitDB. Community discussion is minimal, and the vulnerability is not listed on the CISA KEV catalog or Hot List.

Impacted Technologies

VendorProductVersion(s)CPE
>= 15.10.0, < 20.8.8CPE matchmatch criteria
cpe:2.3:a:capricorn86:happy_dom:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.79%
Probability of exploitation in next 30 days
EPSS Percentile
52.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0079 is in the 36th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: happy-domFixed in: 20.8.8

Vendor Advisories (1)

npmGHSA-6q6h-j7hj-3r64high

Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code

Mar 26, 2026

References

access.redhat.com / security/cve/CVE-2026-33943
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-33943.json
github.com / capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c
Patch
github.com / capricorn86/happy-dom/releases/tag/v20.8.8
ProductRelease Notes
github.com / capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64
ExploitVendor Advisory