CVE-2026-55408Public exploit

Code execution via unsanitized EPUB iframe content

Published Jul 7, 2026 · Updated Jul 7, 2026

Code injection in Koodo Reader 2.3.0 and earlier allows attackers to execute operating system commands through a malicious EPUB file. The open-book IPC handler enables Node.js integration in nested frames, while chapter rendering assigns attacker-controlled HTML directly to innerHTML without sanitization. Opening an imported EPUB instantiates its hidden iframe and runs commands with the local user's privileges; no further interaction is required.

CVSS severity8.4
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Code injection in Koodo Reader 2.3.0 and earlier allows attackers to execute operating system commands through a malicious EPUB file. The open-book IPC handler enables Node.js integration in nested frames, while chapter rendering assigns attacker-controlled HTML directly to innerHTML without sanitization. Opening an imported EPUB instantiates its hidden iframe and runs commands with the local user's privileges; no further interaction is required.

The record

CVE
CVE-2026-55408
Published
Jul 7, 2026
Updated
Jul 7, 2026
Vendor
Koodo Reader
Product
Koodo Reader
Classifications
CWE-94, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.3.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Koodo Reader · Koodo Readerversion=< 2.3.1

Published CVSS scores

8.4GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo