CVE-2025-65858 Calibre-Web Has a Stored Cross-Site Scripting (XSS) Vulnerability via the 'username' Field During User Creation

Low 3.5 Published 2 Dec 2025 Updated 2 Dec 2025

Attackers can inject malicious JavaScript into the username field, leading to script execution when the user list is viewed.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2025-65858?

CVE-2025-65858 is a low-severity cross-site scripting vulnerability in n/a, published on 2 Dec 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official description

A Stored Cross-Site Scripting (XSS) vulnerability in Calibre-Web v0.6.25 allows attackers to inject malicious JavaScript into the 'username' field during user creation. The payload is stored unsanitized and later executed when the /ajax/listusers endpoint is accessed.

Weakness: CWE-79

Which versions are affected by CVE-2025-65858?

3 open source packages ship an affected version, including calibreweb. It affects 1 product.

Package	Affected	Fixed in
`calibreweb` PyPI	All versions to `0.6.25`	None
`calibreweb` PyPI	All versions to `0.6.25`	None
`calibreweb` PyPI	All versions to `0.6.25`	None

Products include Janeczku Calibre-Web.

How do I fix CVE-2025-65858?

No fix has been published for CVE-2025-65858 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-65858 being exploited?

There is no known exploitation of CVE-2025-65858 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as GHSA-pc5g-j9j7-p4q3, PYSEC-2026-1234.