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 84% 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
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.4Exploit: Elevated riskExposed: 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)
EG Risk
54(Track*)
EG Risk 54/100SSVC: 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
Severity84% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
16%
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 11× in last 7d / 49× 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. 2026-09-01 13:54 UTCEPSS rescore
  2. 2026-09-01 04:40 UTCEPSS rescore
  3. 2026-08-30 19:17 UTCEPSS rescore
  4. 2026-08-30 07:42 UTCEG score recompute
  5. 2026-08-30 01:22 UTCEPSS rescore
  6. 2026-08-28 21:41 UTCEPSS rescore
  7. 2026-08-27 21:54 UTCEG score recompute
  8. 2026-08-27 14:25 UTCEPSS rescore
  9. 2026-08-27 01:52 UTCEG score recompute
  10. 2026-08-26 14:46 UTCEPSS rescore
  11. 2026-08-26 12:57 UTCEG score recompute
  12. 2026-08-25 13:49 UTCEPSS rescore
  13. 2026-08-24 20:42 UTCEG score recompute
  14. 2026-08-24 09:48 UTCEG score recompute
  15. 2026-08-22 02:01 UTCEG score recompute
  16. 2026-08-21 23:49 UTCEPSS rescore
  17. 2026-08-21 04:10 UTCEG score recompute
  18. 2026-08-20 22:55 UTCEPSS rescore
  19. 2026-08-20 02:10 UTCEG score recompute
  20. 2026-08-19 17:04 UTCEPSS rescore
  21. 2026-08-18 22:29 UTCEG score recompute
  22. 2026-08-18 13:48 UTCEPSS rescore
  23. 2026-08-17 23:20 UTCEG score recompute
  24. 2026-08-17 13:47 UTCEPSS rescore
  25. 2026-08-17 01:32 UTCEG score recompute
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  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-16 03:43 UTCEG score recompute
  3. 2026-08-16 02:14 UTCEPSS rescore
  4. 2026-08-15 05:55 UTCEG score recompute
  5. 2026-08-15 01:30 UTCEPSS rescore
  6. 2026-08-14 08:07 UTCEG score recompute
  7. 2026-08-13 22:00 UTCEPSS rescore
  8. 2026-08-12 23:21 UTCEG score recompute
  9. 2026-08-12 13:51 UTCEPSS rescore
  10. 2026-08-11 14:40 UTCEG score recompute
  11. 2026-08-11 03:46 UTCEG score recompute
  12. 2026-08-11 00:00 UTCEPSS rescore
  13. 2026-08-09 18:13 UTCEG score recompute
  14. 2026-08-09 13:46 UTCEPSS rescore
  15. 2026-08-07 22:37 UTCEG score recompute
  16. 2026-08-07 00:40 UTCEG score recompute
  17. 2026-08-06 13:47 UTCEPSS rescore
  18. 2026-08-06 02:49 UTCEG score recompute
  19. 2026-08-05 19:17 UTCEPSS rescore
  20. 2026-08-04 15:17 UTCEG score recompute
  21. 2026-08-04 15:10 UTCEPSS rescore
  22. 2026-08-04 10:39 UTCEPSS rescore
  23. 2026-08-03 17:29 UTCEG score recompute
  24. 2026-08-03 10:36 UTCEPSS rescore
  25. 2026-08-02 08:32 UTCEG score recompute
  26. 2026-08-02 02:27 UTCEPSS rescore
  27. 2026-08-01 10:44 UTCEG score recompute
  28. 2026-08-01 04:16 UTCEPSS rescore
  29. 2026-07-31 01:56 UTCEG score recompute
  30. 2026-07-30 16:28 UTCEPSS rescore
  31. 2026-07-30 14:51 UTCEG score recompute
  32. 2026-07-30 03:56 UTCEG score recompute
  33. 2026-07-30 01:30 UTCEPSS rescore
  34. 2026-07-28 19:10 UTCEG score recompute
  35. 2026-07-28 15:37 UTCEPSS rescore
  36. 2026-07-27 21:19 UTCEG score recompute
  37. 2026-07-26 23:28 UTCEG score recompute
  38. 2026-07-26 14:54 UTCEPSS rescore
  39. 2026-07-26 12:34 UTCEG score recompute
  40. 2026-07-25 14:18 UTCEPSS rescore
  41. 2026-07-24 14:18 UTCEPSS rescore
  42. 2026-07-23 14:18 UTCEPSS rescore
  43. 2026-07-23 03:20 UTCEG score recompute
  44. 2026-07-22 14:08 UTCEPSS rescore
  45. 2026-07-21 15:25 UTCEPSS rescore
  46. 2026-07-20 17:08 UTCEPSS rescore
  47. 2026-07-19 14:31 UTCEPSS rescore
  48. 2026-07-19 14:31 UTCEPSS rescore
  49. 2026-07-19 02:29 UTCEPSS rescore
  50. 2026-07-18 10:04 UTCEPSS rescore
  51. 2026-07-16 17:03 UTCEPSS rescore
  52. 2026-07-15 16:57 UTCEPSS rescore
  53. 2026-07-15 16:57 UTCEPSS rescore
  54. 2026-07-15 02:00 UTCEPSS rescore
  55. 2026-07-15 02:00 UTCEPSS rescore
  56. 2026-07-13 22:31 UTCEPSS rescore
  57. 2026-07-13 06:13 UTCEPSS rescore
  58. 2026-07-13 06:13 UTCEPSS rescore
  59. 2026-07-12 05:46 UTCEPSS rescore
  60. 2026-07-11 08:27 UTCEPSS rescore
  61. 2026-07-11 08:27 UTCEPSS rescore
  62. 2026-07-09 19:10 UTCEPSS rescore
  63. 2026-07-09 19:10 UTCEPSS rescore
  64. 2026-07-08 15:16 UTCEPSS rescore
  65. 2026-07-08 15:16 UTCEPSS rescore
  66. 2026-07-07 21:37 UTCEG score recompute
  67. 2026-07-07 21:37 UTCMITRE cvelistV5first tracked

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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 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-2026-55408?
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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