Skip to content
Fencer Intel
medium 6.5

CVE-2026-118661 json

Happy DOM: Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies

published 12d ago modified 6d ago also EUVD-2026-112468 , GHSA-5fpq-26gf-qwcr

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 20.14.6, Happy DOM's CookieContainer in src/cookie/CookieContainer.ts does not correctly validate or match Domain cookie attributes. It can accept a Domain unrelated to the origin setting the cookie, including a public suffix, and separately treats an unrelated suffix-sharing hostname as a match because cookieMatchesURL does not enforce a DNS-label boundary. In server-side rendering and prerendering applications that contact attacker-controlled origins and then make requests to a victim origin, these behaviors can plant and deliver a forged cookie, enabling cookie injection or session fixation. This issue is fixed in version 20.14.6.

Patch / fix

  • npm happy-dom 20.14.6
  • capricorn86 happy_dom 20.14.6

Is CVE-2026-118661 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.

Check with Fencer

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-2026-118661 updated cvss 6.5

happy-dom: happy-dom: Cookie injection via improper cookie domain validation

  • 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 available, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-feature-server-rhel9
    affected: no fix available “Fix deferred”

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
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6d ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm happy-dom
<20.14.6
20.14.6

Affected products

  • capricorn86 happy-dom

Classification

Weakness
  • CWE-565 Reliance on Cookies without Validation and Integrity Checking

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.