ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-33943

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface.

Published Mar 27, 2026 · catalog updated Jul 15, 2026 · happy dom

Check if you run it

No confirmed exploitation is on record for CVE-2026-33943. EPSS is 0.97%. Act only if a listed version of happy dom is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.97%
Remediation
Advisory link
Affected products
cpe capricorn86/happy dom

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization. Version 20.8.8 fixes the issue.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe capricorn86/happy domversion unspecified

How to fix CVE-2026-33943

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33943. EPSS is 0.97%. Act only if a listed version of happy dom is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-917: Expression Language Injection; CWE-94: Code Injection. EPSS 0.97%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 27, 2026 · NIST NVD

    Detected

    Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into gener

  2. Jul 15, 2026 · NIST NVD

    Updated

    Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into gener

Sources

  • CVE.orgVulnerability recordCVE-2026-33943

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33943

    30-day exploitation probability 1.0%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33943

    Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaSc

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.