CVE-2026-55240

CRITICAL
INFO Priority: 0.07 BB Relevance: 63/100
Published: 2026-10-15 Modified: 2026-10-28 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Conf. Impact Integ. Impact Scope Change

CVSS Vector Breakdown

AV: Network
AC: Low
PR: High
UI: None
S: Changed
C: High
I: High
A: High

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
msgbyte tianji < 1.31.29

Bug Bounty Relevance

63 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

9.1 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploitation Probability

0.75%
Raw Score 0.007480
Percentile 54.8%
Date 2026-10-30

EPSS Trend

2026-10-30
0.00748
2026-10-29
0.00748
2026-10-28
0.00576

Intelligence Sources

mitre ref →
nvd ref →