Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M

CVE-2026-55240Tianji: Remote Code Execution via lodash template evaluate pattern in survey feed templates

Critical 9.1

In plain English

A critical-severity security flaw in tianji from msgbyte. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.7%top 44.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Tianji is an open source analytics, uptime monitoring, and server status platform. Prior to 1.31.29, formatString() in src/server/utils/template.ts passes survey feedTemplate and monitor notification templates to lodash template(), while the default evaluate pattern remains enabled. A workspace administrator can store an evaluate block using the <% code %> form, and the public survey.submit endpoint renders a survey template when an unauthenticated user submits a response. The compiled template executes server-side JavaScript in the Tianji Node.js process, allowing command execution, secret disclosure, data modification, or service disruption. This issue is fixed in version 1.31.29.

Affected products (as reported)

Vendor	Product	Versions
msgbyte	tianji	< 1.31.29

Weakness: CWE-1336 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/msgbyte/tianji/security/advisories/GHSA-5grg-j3cr-3hpm x_refsource_CONFIRM
https://github.com/msgbyte/tianji/commit/132ff67907df897d222829ea8ad1a018ff74df48 x_refsource_MISC
https://github.com/msgbyte/tianji/releases/tag/v1.31.29 x_refsource_MISC