Tiptap: mergeAttributes() turns an own __proto__ key into inherited executable DOM attributes — GHSA-CP6Q-959Q-F8RH

Summary

## Summary `@tiptap/core`'s public `mergeAttributes()` helper uses ordinary bracket assignment on keys returned by `Object.entries()`. An own `__proto__` key from JSON therefore invokes the legacy prototype setter on the fresh merged object. The function returns an object whose prototype is attacker-controlled, while `Object.keys()` and ordinary own-property checks show no attacker attributes. When that result is…

Timeline

Published by source

2026-09-02

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 6.4 out of 10.
• Review exposure for the affected product or family: npm: @tiptap/core.

Product

npm: @tiptap/core

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source

Evidence and provenance

Canonical advisory ID

GHSA-CP6Q-959Q-F8RH

Source

GitHub

Vendor

GitHub

Published by source

2026-09-02

Last source activity

2026-09-02

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.