Is this vulnerability remotely exploitable?

Not in a traditional networked sense. Exploitation occurs when a user locally opens or converts a malicious EPUB file with Calibre. However, attackers can distribute such EPUB files via the internet, email, or online libraries to reach victims.

What level of access does an attacker need?

The attacker only needs to get a victim to process a crafted EPUB with a vulnerable Calibre version. The attack then runs with the filesystem permissions of the Calibre process on that user's system, limited by what that process can write.

What is the safest general fix pattern?

The best fix is to enforce strict path confinement for all file references derived from EPUB content. All CipherReference URIs should be canonicalized and verified to stay within a fixed working directory, with absolute paths and traversal attempts rejected outright, and file access reduced to the minimum privileges required.

Severity:

HIGH RISK

(8.2)

Path Traversal (CWE-22) in Calibre EPUB Conversion CipherReference Handling

CVE-2026-25636

Published:

Feb 6, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

Path Traversal

CWE:

CWE-22;CWE-73;CWE-94

Impact:

Arbitrary File Corruption / Overwrite in Local Context

Severity:

HIGH RISK

(8.2)

CVSS Version:

3.1

Vulnerability Type

Category:

Path Traversal

CWE:

CWE-22;CWE-73;CWE-94

Impact:

Arbitrary File Corruption / Overwrite in Local Context

Severity:

HIGH RISK

(8.2)

CVSS Version:

3.1

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Ask AI for summary of CodeAnt

Path Traversal (CWE-22) in Calibre EPUB Conversion CipherReference Handling

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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