CVE-2026-8623

MEDIUMPre-NVD 6.46.4—
EchelonGraph scoreHIGH confidence

Score 6.4 from GitHub Security Advisory published 2026-09-05. a secondary CVSS source baseline 6.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.4Exploit: None knownExposed: 0

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

The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PDF viewer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'post_content (class attribute of .dvcss element)' parameter in all versions up to, and including, 2.4.30 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is embedded as a Base64-encoded JSON object in a CSS class name on a Custom HTML block; the frontend parseCSSElements() function decodes it client-side with atob() and JSON.parse() and renders the logo property as raw HTML, meaning no server-side or client-side sanitization intercepts the malicious script before DOM insertion.

CVSS v3
6.4
EG Score
6.4(high)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity64% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

September 5, 2026

Last Modified

September 8, 2026

References (6)

Vendor Advisories for CVE-2026-8623(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 64× 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. 2026-09-25 11:42 UTCEG score recompute
  2. 2026-09-25 11:42 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-24 13:09 UTCEG score recompute
  5. 2026-09-24 13:09 UTCGHSA enrichment
  6. 2026-09-23 17:54 UTCEPSS rescore
  7. 2026-09-23 14:42 UTCGHSA enrichment
  8. 2026-09-22 16:14 UTCEG score recompute
  9. 2026-09-22 16:14 UTCGHSA enrichment
  10. 2026-09-22 16:01 UTCEPSS rescore
  11. 2026-09-21 21:09 UTCEPSS rescore
  12. 2026-09-21 17:46 UTCEG score recompute
  13. 2026-09-21 17:46 UTCGHSA enrichment
  14. 2026-09-20 20:16 UTCEPSS rescore
  15. 2026-09-20 19:18 UTCGHSA enrichment
  16. 2026-09-19 20:51 UTCEG score recompute
  17. 2026-09-19 20:51 UTCGHSA enrichment
  18. 2026-09-18 22:23 UTCEG score recompute
  19. 2026-09-18 22:23 UTCGHSA enrichment
  20. 2026-09-18 19:28 UTCEPSS rescore
  21. 2026-09-17 23:56 UTCEG score recompute
  22. 2026-09-17 23:56 UTCGHSA enrichment
  23. 2026-09-17 19:32 UTCEPSS rescore
  24. 2026-09-17 00:29 UTCEG score recompute
  25. 2026-09-17 00:29 UTCGHSA enrichment
Show 39 more
  1. 2026-09-16 14:09 UTCEPSS rescore
  2. 2026-09-16 05:15 UTCEPSS rescore
  3. 2026-09-16 02:01 UTCGHSA enrichment
  4. 2026-09-15 03:33 UTCEG score recompute
  5. 2026-09-15 03:33 UTCGHSA enrichment
  6. 2026-09-15 03:12 UTCEPSS rescore
  7. 2026-09-14 05:05 UTCEG score recompute
  8. 2026-09-14 05:05 UTCGHSA enrichment
  9. 2026-09-13 16:48 UTCEPSS rescore
  10. 2026-09-13 06:38 UTCEG score recompute
  11. 2026-09-13 06:38 UTCGHSA enrichment
  12. 2026-09-12 15:02 UTCEPSS rescore
  13. 2026-09-12 08:11 UTCEG score recompute
  14. 2026-09-12 08:11 UTCGHSA enrichment
  15. 2026-09-11 14:53 UTCEPSS rescore
  16. 2026-09-11 09:44 UTCEG score recompute
  17. 2026-09-11 09:43 UTCGHSA enrichment
  18. 2026-09-11 09:38 UTCEPSS rescore
  19. 2026-09-10 11:15 UTCEG score recompute
  20. 2026-09-10 11:15 UTCGHSA enrichment
  21. 2026-09-09 12:44 UTCEG score recompute
  22. 2026-09-09 12:44 UTCGHSA enrichment
  23. 2026-09-08 22:01 UTCEPSS rescore
  24. 2026-09-08 14:16 UTCGHSA enrichment
  25. 2026-09-08 10:59 UTCEG score recompute
  26. 2026-09-08 10:59 UTCGHSA enrichment
  27. 2026-09-07 12:27 UTCEG score recompute
  28. 2026-09-07 12:26 UTCGHSA enrichment
  29. 2026-09-07 11:28 UTCEG score recompute
  30. 2026-09-07 11:28 UTCGHSA enrichment
  31. 2026-09-07 03:22 UTCEG score recompute
  32. 2026-09-07 03:22 UTCGHSA enrichment
  33. 2026-09-06 13:48 UTCEPSS rescore
  34. 2026-09-06 04:52 UTCEG score recompute
  35. 2026-09-06 04:52 UTCGHSA enrichment
  36. 2026-09-05 15:31 UTCEPSS rescore
  37. 2026-09-05 06:25 UTCEG score recompute
  38. 2026-09-05 05:39 UTCEG score recompute
  39. 2026-09-05 05:38 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8623?
CVE-2026-8623 is a medium vulnerability published on September 5, 2026. The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PDF viewer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'post_content (class attribute of .dvcss element)' parameter in all versions up to, and including, 2.4.30 due to insufficient input sanitization and output…
When was CVE-2026-8623 disclosed?
CVE-2026-8623 was first published in the National Vulnerability Database on September 5, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8623 actively exploited?
CVE-2026-8623 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 74.3% of all scored CVEs.
What is the CVSS score of CVE-2026-8623?
CVE-2026-8623 has a CVSS v3 base score of 6.4 (NVD).
How do I remediate CVE-2026-8623?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8623, 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

Explore the affected products and dependency analysis for CVE-2026-8623

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