# CVE-2025-65858: A Stored Cross-Site Scripting (XSS) vulnerability in Calibre-Web v0.6.25 allows attackers to inject malicious JavaScript into the 'username'

Source: https://junglewise.ai/threats/cve-2025-65858-calibre-web-has-a-stored-cross-site-scripting-xss-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-12-02  
License: CC BY 4.0 with a link back

CVE-2025-65858 · Severity: medium · CVSS 4 · Published 2025-12-02

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.

Technologies: [calibreweb (PyPI)](https://junglewise.ai/threats/technologies/calibreweb). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2025-65858 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-65858 being exploited in the wild.

**How severe is CVE-2025-65858?** Medium severity, with a CVSS score of 4, published 2 December 2025.

**Which products and versions are affected?** calibreweb (PyPI) ECOSYSTEM:introduced=0,last_affected=0.6.25.

**Is there a fix for CVE-2025-65858?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2025-65858?** Check whether you run Janeczku Calibre-Web or calibreweb (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Janeczku Calibre-Web
- calibreweb (PyPI) ECOSYSTEM:introduced=0,last_affected=0.6.25

## Identifiers

- CVE-2025-65858
- GHSA-pc5g-j9j7-p4q3
- PYSEC-2026-1234

## Related threats

- [PYSEC-2026-1228 - Calibre Web and Autocaliweb have a ReDoS vulnerability](https://junglewise.ai/threats/cve-2025-6998-calibre-web-and-autocaliweb-redos-in-strip-whitespaces)
- [PYSEC-2026-1235 - Calibre Web and Autocaliweb have OS Command Injection vulnerability](https://junglewise.ai/threats/cve-2025-7404-calibre-web-and-autocaliweb-have-os-command-injection)
- [PYSEC-2026-1232 - Generation of Error Message Containing Sensitive Information in janeczku/calibre-web](https://junglewise.ai/threats/cve-2021-3986-generation-of-error-message-containing-sensitive-information-in)
- [PYSEC-2026-1236 - Cross-site Scripting (XSS) - DOM in janeczku/calibre-web](https://junglewise.ai/threats/cve-2021-3988-cross-site-scripting-xss-dom-in-janeczku-calibre-web)
- [PYSEC-2026-1229 - Improper Access Control in janeczku/calibre-web](https://junglewise.ai/threats/cve-2021-3987-improper-access-control-in-janeczku-calibre-web)