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Fencer Vulns
medium 4.6

CVE-2026-73428 json

Trix: Stored XSS via HTMLParser attribute injection on paste

published 2026-07-24 3 mo ago modified 2026-09-18 51 d ago also GHSA-53g2-mvcc-q9x3 , EUVD-2026-58520

cvss
4.6
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 29%
public exploits
0
none known

Summary

Trix is a what-you-see-is-what-you-get rich text editor for everyday writing. Prior to 2.1.18, Trix is vulnerable to stored cross-site scripting when crafted HTML is pasted into the editor. HTMLParser processes a mock attachment in a `<span>` with an empty `data-trix-attachment="{}"` value, causing data-trix-attributes to be applied to a plain string piece. StringPiece.fromJSON accepts an unvalidated href, allowing a javascript: URI to enter the document model and serialized HTML and execute when another user renders and clicks the content. Applications that apply server-side HTML sanitization can neutralize the payload on save. This issue is fixed in version 2.1.18.

Patch / fix

  • npm trix 2.1.18
  • rubygems action_text-trix 2.1.18

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-2026-73428 updated cvss 4.6

trix: action_text-trix: Trix: Stored Cross-Site Scripting via HTML paste allows arbitrary code execution.

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

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
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 4.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm trix
<2.1.18
2.1.18
rubygems action_text-trix
<2.1.18
2.1.18

Affected products

  • basecamp trix

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns 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.