Trix: Stored XSS via HTMLParser attribute injection on paste
Published Aug 13, 2026
4.6
MEDIUMCVSS 3.1
EPSS 0.35%
Description
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.
Affected products
-
- Version < 2.1.18StatusaffectedConstraints-
- Version
No data.
No data.
No Red Hat product state for this CVE.
trix
npm
Introduced 0 Fixed 2.1.18action_text-trix
RubyGems
Introduced 0 Fixed 2.1.18
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | trix | 0 | 2.1.18 |
| RubyGems | action_text-trix | 0 | 2.1.18 |
Remediation
Red Hat statement
No Red Hat products ship a vulnerable version of this component.
Red Hat mitigation
Applications that apply server-side HTML sanitization can neutralize the XSS payload on save, preventing exploitation even on unpatched versions of Trix.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed Aug 14, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
Aug–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.35% (0.00353) | 26.61th | v5 (v2026.06.15) |
| Aug 14, 2026 | 0.17% (0.00171) | 6.79th | v5 (v2026.06.15) |
References (9)
- https://access.redhat.com/security/cve/CVE-2026-73428 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2515813 Issue Tracking
- https://github.com/advisories/GHSA-53g2-mvcc-q9x3 Advisory
- https://github.com/basecamp/trix/commit/9c0a993d9fc2ffe9d56b013b030bc238f9c0557c x_refsource_MISC
- https://github.com/basecamp/trix/pull/1293 x_refsource_MISC
- https://github.com/basecamp/trix/releases/tag/v2.1.18 x_refsource_MISC
- https://github.com/basecamp/trix/security/advisories/GHSA-53g2-mvcc-q9x3 x_refsource_CONFIRM
- https://nvd.nist.gov/vuln/detail/CVE-2026-73428
- https://www.cve.org/CVERecord?id=CVE-2026-73428
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-73428 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2515813 | Issue Tracking | |
| https://github.com/advisories/GHSA-53g2-mvcc-q9x3 | Advisory | |
| https://github.com/basecamp/trix/commit/9c0a993d9fc2ffe9d56b013b030bc238f9c0557c | x_refsource_MISC | |
| https://github.com/basecamp/trix/pull/1293 | x_refsource_MISC | |
| https://github.com/basecamp/trix/releases/tag/v2.1.18 | x_refsource_MISC | |
| https://github.com/basecamp/trix/security/advisories/GHSA-53g2-mvcc-q9x3 | x_refsource_CONFIRM | |
| https://nvd.nist.gov/vuln/detail/CVE-2026-73428 | ||
| https://www.cve.org/CVERecord?id=CVE-2026-73428 |
Change history (0)
No recorded changes yet.