CVE-2026-55240
Tianji: Remote Code Execution via lodash template evaluate pattern in survey feed templates
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
9.1
Tianji: Remote Code Execution via lodash template evaluate pattern in survey feed templates
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.
- Record
CVE-2026-55240- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-1336
- Updated
- 2026-11-02
EUVDEUVD-2026-102246
9.1
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.
- Record
EUVD-2026-102246- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
NVD
9.1
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.
- Record
CVE-2026-55240- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-1336
- Updated
- 2026-11-02
OSV
9.1
Tianji: Remote Code Execution via lodash template evaluate pattern in survey feed templates
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.
- Record
CVE-2026-55240- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-1336
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-55240 is a critical vulnerability (CVSS 9.1) in Msgbyte Tianji, published October 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.75%, the 55th percentile. No source names a fixed version.
References
github.com/msgbyte/tianji/security/advisories/GHSA-5grg-j3cr-3hpm
github.com/msgbyte/tianji/commit/132ff67907df897d222829ea8ad1a018ff74df48
github.com/msgbyte/tianji/releases/tag/v1.31.29
github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55240.json
nvd.nist.gov/vuln/detail/CVE-2026-55240