CVE-2026-8661: Server-Side Cross-Site Scripting and SSRF in Rapid7 InsightConnect Markdown to PDF Plugin
Vulnerability summary
CVE-2026-8661 is a medium (CVSS 4.8) Cross-site Scripting vulnerability in rapid7 insightconnect markdown plugin. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.3% of scored vulnerabilities.
Timeline
- 26-06-2026PublishedVulnerability first disclosed.
- 24-07-2026Last modifiedVulnerability information updated.
Description
Server-Side Request Forgery in the markdown_to_pdf action of Rapid7 InsightConnect Markdown Plugin on Linux in versions prior to 4.0.2 allows remote attackers to make arbitrary outbound HTTP requests via unsanitized resource-loading HTML elements (img/src, CSS url(), @import) embedded in Markdown input. The initial fix in 4.0.0 disabled JavaScript but did not neutralize resource-loading vectors. Resolved in 4.0.2 by sanitizing HTML with an allowlist of tags, attributes, and URL schemes.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST4.8MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS trend
Probability
0.38%
Chance of exploitation in the next 30 days
Percentile
30%
Versus all other CVEs
30-day change
Increase +0.13 pp
From 0.24% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')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.
- CWE-918Server-Side Request Forgery (SSRF)The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Affected systems
Rapid71 product
1 vendor · 1 product