CVE-2026-8661

MEDIUMPre-NVD 4.84.8—
EchelonGraph scoreMEDIUM confidence

Score 4.8 from GitHub Security Advisory published 2026-06-26. a secondary CVSS source baseline 4.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
4.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
4.8
EG Score
4.8(medium)
EG Risk
22(Track)
EG Risk 22/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity48% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
16%
KEV
Not listed

Published

June 26, 2026

Last Modified

July 24, 2026

Advisory Details (2)

Auto-updated Jun 26, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

Markdown SDK Bump and Spec Cleanup

Fix merged in rapid7/insightconnect-plugins PR #3721 on 2026-02-12 — awaiting tagged release

https://github.com/rapid7/insightconnect-plugins/pull/3721
generic

insightconnect-plugins/plugins/markdown/help.md at master · rapid7/insightconnect-plugins · GitHub

https://github.com/rapid7/insightconnect-plugins/blob/master/plugins/markdown/help.md

Vendor Advisories for CVE-2026-8661(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 59× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 06:26 UTCEG score recompute
  2. 2026-07-27 06:26 UTCGHSA enrichment
  3. 2026-07-26 14:54 UTCEPSS rescore
  4. 2026-07-26 05:11 UTCEG score recompute
  5. 2026-07-26 05:11 UTCGHSA enrichment
  6. 2026-07-25 14:18 UTCEPSS rescore
  7. 2026-07-24 14:18 UTCEPSS rescore
  8. 2026-07-23 14:18 UTCEPSS rescore
  9. 2026-07-23 03:23 UTCEG score recompute
  10. 2026-07-22 14:08 UTCEPSS rescore
  11. 2026-07-21 15:25 UTCEPSS rescore
  12. 2026-07-21 15:25 UTCEPSS rescore
  13. 2026-07-20 17:08 UTCEPSS rescore
  14. 2026-07-19 14:31 UTCEPSS rescore
  15. 2026-07-19 02:29 UTCEPSS rescore
  16. 2026-07-18 10:04 UTCEPSS rescore
  17. 2026-07-17 03:06 UTCGHSA enrichment
  18. 2026-07-16 17:03 UTCEPSS rescore
  19. 2026-07-16 01:57 UTCGHSA enrichment
  20. 2026-07-15 16:57 UTCEPSS rescore
  21. 2026-07-15 02:00 UTCEPSS rescore
  22. 2026-07-15 00:49 UTCGHSA enrichment
  23. 2026-07-13 23:39 UTCGHSA enrichment
  24. 2026-07-13 22:31 UTCEPSS rescore
  25. 2026-07-13 06:13 UTCEPSS rescore
Show 38 more
  1. 2026-07-12 22:31 UTCGHSA enrichment
  2. 2026-07-12 05:46 UTCEPSS rescore
  3. 2026-07-11 21:22 UTCGHSA enrichment
  4. 2026-07-11 08:27 UTCEPSS rescore
  5. 2026-07-10 20:15 UTCGHSA enrichment
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-09 19:07 UTCGHSA enrichment
  8. 2026-07-08 17:55 UTCGHSA enrichment
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-07 16:47 UTCGHSA enrichment
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 15:39 UTCGHSA enrichment
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-06 02:23 UTCEPSS rescore
  17. 2026-07-05 14:27 UTCGHSA enrichment
  18. 2026-07-05 02:31 UTCEPSS rescore
  19. 2026-07-05 02:30 UTCEPSS rescore
  20. 2026-07-04 13:19 UTCGHSA enrichment
  21. 2026-07-04 06:31 UTCEPSS rescore
  22. 2026-07-04 06:31 UTCEPSS rescore
  23. 2026-07-03 12:10 UTCGHSA enrichment
  24. 2026-07-02 10:58 UTCGHSA enrichment
  25. 2026-07-02 10:56 UTCGHSA enrichment
  26. 2026-07-01 15:07 UTCEPSS rescore
  27. 2026-07-01 09:29 UTCGHSA enrichment
  28. 2026-06-30 23:22 UTCEPSS rescore
  29. 2026-06-30 08:21 UTCGHSA enrichment
  30. 2026-06-29 14:06 UTCEPSS rescore
  31. 2026-06-29 07:13 UTCGHSA enrichment
  32. 2026-06-28 14:07 UTCEPSS rescore
  33. 2026-06-28 06:05 UTCGHSA enrichment
  34. 2026-06-28 04:56 UTCEPSS rescore
  35. 2026-06-27 04:55 UTCGHSA enrichment
  36. 2026-06-27 03:08 UTCEPSS rescore
  37. 2026-06-26 03:46 UTCEG score recompute
  38. 2026-06-26 03:46 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8661?
CVE-2026-8661 is a medium vulnerability published on June 26, 2026. Server-Side Request Forgery in the markdowntopdf 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…
When was CVE-2026-8661 disclosed?
CVE-2026-8661 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8661 actively exploited?
CVE-2026-8661 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 84.2% of all scored CVEs.
What is the CVSS score of CVE-2026-8661?
CVE-2026-8661 has a CVSS v3 base score of 4.8 (NVD).
How do I remediate CVE-2026-8661?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8661, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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