CVE-2026-55408

HIGHPre-NVD 8.48.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
8.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.4Exploit: NoneExposed: 0

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

Koodo Reader is an ebook reader. In version 2.3.0 and earlier, Koodo Reader is vulnerable to remote code execution through malicious EPUB files because the open-book IPC handler enables nodeIntegrationInSubFrames and EPUB chapter content is rendered with unsanitized innerHTML. An attacker can craft an EPUB book that, when imported and opened by the victim, instantiates a hidden iframe with Node.js API access and executes arbitrary operating system commands with the victim user's privileges. This issue is fixed in version 2.3.1.

CVSS v3
8.4
EG Score
8.4(medium)
EPSS
8.5%
KEV
Not listed

Published

July 7, 2026

Last Modified

July 8, 2026

Advisory Details (1)

Auto-updated Jul 7, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Remote code execution via malicious epub file · Advisory · koodo-reader/koodo-reader · GitHub

https://github.com/koodo-reader/koodo-reader/security/advisories/GHSA-mjr7-w4jq-2rq9

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 28× in last 7d / 34× 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. 2026-07-16 02:09 UTCEG score recompute
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 16:57 UTCEPSS rescore
  4. 2026-07-15 15:14 UTCEG score recompute
  5. 2026-07-15 04:20 UTCEG score recompute
  6. 2026-07-15 02:00 UTCEPSS rescore
  7. 2026-07-15 02:00 UTCEPSS rescore
  8. 2026-07-14 17:21 UTCEG score recompute
  9. 2026-07-14 06:26 UTCEG score recompute
  10. 2026-07-13 22:31 UTCEPSS rescore
  11. 2026-07-13 19:31 UTCEG score recompute
  12. 2026-07-13 08:36 UTCEG score recompute
  13. 2026-07-13 06:13 UTCEPSS rescore
  14. 2026-07-13 06:13 UTCEPSS rescore
  15. 2026-07-12 21:42 UTCEG score recompute
  16. 2026-07-12 10:48 UTCEG score recompute
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 23:53 UTCEG score recompute
  19. 2026-07-11 12:59 UTCEG score recompute
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-11 02:05 UTCEG score recompute
  23. 2026-07-10 15:11 UTCEG score recompute
  24. 2026-07-10 04:15 UTCEG score recompute
  25. 2026-07-09 19:10 UTCEPSS rescore
Show 9 more
  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-09 17:21 UTCEG score recompute
  3. 2026-07-09 06:22 UTCEG score recompute
  4. 2026-07-08 19:28 UTCEG score recompute
  5. 2026-07-08 15:16 UTCEPSS rescore
  6. 2026-07-08 15:16 UTCEPSS rescore
  7. 2026-07-08 08:32 UTCEG score recompute
  8. 2026-07-07 21:37 UTCEG score recompute
  9. 2026-07-07 21:37 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-55408?
CVE-2026-55408 is a high vulnerability published on July 7, 2026. Koodo Reader is an ebook reader. In version 2.3.0 and earlier, Koodo Reader is vulnerable to remote code execution through malicious EPUB files because the open-book IPC handler enables nodeIntegrationInSubFrames and EPUB chapter content is rendered with unsanitized innerHTML. An attacker can craft…
When was CVE-2026-55408 disclosed?
CVE-2026-55408 was first published in the National Vulnerability Database on July 7, 2026, with the most recent update on July 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55408 actively exploited?
CVE-2026-55408 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 8.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55408?
CVE-2026-55408 has a CVSS v3 base score of 8.4 (NVD).
How do I remediate CVE-2026-55408?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55408, 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.

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