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Fencer Intel
high 8.6

CVE-2026-118660 json

Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML

published 12d ago modified 11d ago also EUVD-2026-112467 , GHSA-c8p4-j97h-3vg8

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.0, Happy DOM loads iframe src URLs and link rel="stylesheet" href URLs by default while parsing untrusted HTML on the server because disableIframePageLoading and disableCSSFileLoading default to false. An attacker who controls parsed HTML can therefore cause server-side requests to arbitrary internal or cloud endpoints without an application opt-in and may expose confidential responses or credentials returned by those endpoints. This issue is fixed in version 21.0.0.

Patch / fix

  • npm happy-dom 21.0.0
  • capricorn86 happy_dom 21.0.0

Is CVE-2026-118660 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-118660 updated cvss 5.3

happy-dom: happy-dom: Server-Side Request Forgery via default loading of external resources

  • Red Hat Ansible Automation Platform 2 automation-platform-ui 2.6.15-1.el9ap, automation-gateway 2.5.20260923-1.el9ap, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-27/gateway-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-feature-server-rhel9
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
11d ago

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm happy-dom
<21.0.0
21.0.0

Affected products

  • capricorn86 happy-dom

Classification

Weakness
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.