dbcve.org
Code InjectionWeakness · CWE-94

CVE-2026-55408

HIGH · 8.4 CVSS v4.0 Published 2026-07-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
No privileges 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Koodo Reader versions 2.3.0 and earlier are vulnerable to remote code execution via malicious EPUB files. The open-book IPC handler enables nodeIntegrationInSubFrames, and EPUB chapter content is rendered using unsanitized innerHTML. An attacker can embed malicious JavaScript in an EPUB that, when imported and opened, creates a hidden iframe with Node.js API access to execute arbitrary OS commands with the victim's user privileges.

MitigationUpgrade Koodo Reader to version 2.3.1 or later. Avoid importing EPUB files from untrusted sources until the update is applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
Authentication
X
User interaction
A
Scope
X

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Koodo Reader is installed
    Search for Koodo Reader in your system: on Windows check Program Files, on Mac check /Applications, on Linux check /opt or ~/.local/share. Look for the Koodo Reader executable or application folder.
    Affected if Koodo Reader software is found on the system
  2. Check the installed version
    Open Koodo Reader and navigate to Settings > About, or right-click the application and select Properties to view version information. Compare against affected versions: 2.3.0 and earlier are vulnerable.
    Affected if The installed version is 2.3.0 or any earlier version number
  3. Identify recently imported EPUB files
    Check the Koodo Reader library folder (typically in the user data directory under /library or /storage) for EPUB files imported around the time of potential compromise. Review file sources if known.
    Affected if Any EPUB files from untrusted or unknown sources have been imported into the library
  4. Inspect for suspicious hidden iframes
    While Koodo Reader is running with a book open, use the built-in developer tools (Help > Toggle Developer Tools > Elements tab) and search for iframe tags, especially hidden ones (style display:none or positioned off-screen).
    Affected if Hidden iframes are present in the rendered content that were not intentionally added
  5. Check for unexpected child processes
    Use system monitoring tools (Task Manager on Windows, Activity Monitor on Mac, htop/top on Linux) to look for suspicious node.exe or electron processes spawned by Koodo Reader that are executing unknown commands.
    Affected if Unexpected node or electron child processes are running under your user account

If Koodo Reader version 2.3.0 or earlier is installed and any EPUB from untrusted sources has been imported, the environment is likely affected by this vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Koodo Reader to version 2.3.1 or later. Avoid importing EPUB files from untrusted sources until the update is applied.

Recommended fix High confidence

Koodo Reader 2.3.1

  1. Close Koodo Reader if it is currently running
  2. Download Koodo Reader version 2.3.1 from the official GitHub releases page or the project website
  3. Install the updated version of Koodo Reader (either by running the installer or replacing the existing installation)
  4. Launch Koodo Reader and verify that the application starts without errors

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-55408 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data