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01 Record

CVE-2026-33943

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

HighPUBLISHEDCNA: GitHub_M
CNA base score8.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

02 Description

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

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.64% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 50.6% of scored records. A rank, not a probability.
NVD base score
9.8 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-10-26.
Red Hat severity
Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-03-27 21:15Z7 MO AGO
Last updated
2026-07-15 01:05Z3 MO AGO
Reserved
2026-03-24
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
High (CVSS 8.8)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weaknesses
  • CWE-94Improper Control of Generation of Code ('Code Injection')Base
  • CWE-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')Base
Data version
5.2
Document digest
6b9afe30e8ea5e3761dac342fac323ad9d80120fdc6f171a697cfe34a363db44

05 Affected products

VendorProductVersionsPlatforms
capricorn86happy-dom>= 15.10.0, < 20.8.8—

06 References