Rapid7 InsightConnect Markdown Plugin up to 3.x on Linux markdown_to_pdf cross site scripting

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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3.9$0-$5k1.90-

Summaryinfo

A vulnerability marked as problematic has been reported in Rapid7 InsightConnect Markdown Plugin up to 3.x on Linux. The affected element is the function markdown_to_pdf. The manipulation leads to cross site scripting. This vulnerability is referenced as CVE-2026-8661. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Rapid7 InsightConnect Markdown Plugin up to 3.x on Linux. This issue affects the function markdown_to_pdf. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

Server-Side Cross-Site Scripting and Server-Side Request Forgery vulnerability in the markdown_to_pdf action of Rapid7 InsightConnect Markdown Plugin version 3.1.4 and earlier on Linux allows remote attackers to execute JavaScript server-side and make arbitrary outbound HTTP requests via crafted content embedded in Markdown input. The PDF rendering engine does not restrict script execution or outbound network access.

The weakness was published by Jacob Steadman and Jed Starr. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-8661 since 05/15/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 4.0.0 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.9
VulDB Meta Temp Score: 3.9

VulDB Base Score: 3.1
VulDB Temp Score: 3.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.8
CNA Vector (rapid7): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: InsightConnect Markdown Plugin 4.0.0
Patch: github.com

Timelineinfo

05/15/2026 CVE reserved
06/26/2026 +42 days Advisory disclosed
06/26/2026 +0 days VulDB entry created
06/26/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Researcher: Jacob Steadman, Jed Starr
Status: Confirmed

CVE: CVE-2026-8661 (🔒)
GCVE (CVE): GCVE-0-2026-8661
GCVE (VulDB): GCVE-100-374105

Entryinfo

Created: 06/26/2026 07:40
Changes: 06/26/2026 07:40 (67)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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