VDB-356629 · CVE-2026-39980 · WID-SEC-2026-1036

OpenCTI up to 6.9.4 safeEjs.ts special elements used in a template engine

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.8	$0-$5k	0.00

Summaryinfo

A vulnerability was found in OpenCTI up to 6.9.4. It has been rated as problematic. This impacts an unknown function of the file safeEjs.ts. This manipulation causes improper neutralization of special elements used in a template engine. The identification of this vulnerability is CVE-2026-39980. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in OpenCTI up to 6.9.4 and classified as problematic. Affected by this vulnerability is an unknown function of the file safeEjs.ts. The manipulation with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. The CWE definition for the vulnerability is CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 6.9.5, the safeEjs.ts file does not properly sanitize EJS templates. Users with the Manage customization capability can run arbitrary JavaScript in the context of the OpenCTI platform process during notifier template execution. This vulnerability is fixed in 6.9.5.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-39980 since 04/08/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1221 for this issue.

Upgrading to version 6.9.5 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1036). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

Open Source OpenCTI

Productinfo

Name

OpenCTI

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.9
VulDB Meta Temp Score: 6.8

VulDB Base Score: 4.7
VulDB Temp Score: 4.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper neutralization of special elements used in a template engine
CWE: CWE-1336 / CWE-791 / CWE-790
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: OpenCTI 6.9.5

Timelineinfo

04/08/2026 CVE reserved
04/09/2026 +1 days Advisory disclosed
04/09/2026 +0 days VulDB entry created
04/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-39980 (🔒)
GCVE (CVE): GCVE-0-2026-39980
GCVE (VulDB): GCVE-100-356629
CERT Bund: WID-SEC-2026-1036 - OpenCTI: Schwachstelle ermöglicht Codeausführung

Entryinfo

Created: 04/09/2026 19:44
Updated: 04/09/2026 23:58
Changes: 04/09/2026 19:44 (62), 04/09/2026 23:58 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.