CVE-2026-73427Network attack vector

Cross-site scripting via unsanitized deserialized href

Published Aug 12, 2026 · Updated Aug 12, 2026

Cross-site scripting in 37signals Trix before 2.1.18 allows remote attackers to execute JavaScript through a dropped JSON payload. StringPiece.fromJSON copies an untrusted href into document attributes without DOMPurify validation, so a javascript URI reaches the DOM. Exploitation requires a victim to drag attacker-controlled content into an editor using fallback Level0InputController; server-side sanitization neutralizes the payload on save.

CVSS severity2.1
Low
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in 37signals Trix before 2.1.18 allows remote attackers to execute JavaScript through a dropped JSON payload. StringPiece.fromJSON copies an untrusted href into document attributes without DOMPurify validation, so a javascript URI reaches the DOM. Exploitation requires a victim to drag attacker-controlled content into an editor using fallback Level0InputController; server-side sanitization neutralizes the payload on save.

The record

CVE
CVE-2026-73427
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
37signals
Product
Trix
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.1.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

37signals · Trixversion=< 2.1.18

Published CVSS scores

2.1GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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