---
id: CVE-2025-6998
aliases:
  - GHSA-2g7m-ph9x-7q7m
  - PYSEC-2026-1228
title: Calibre Web and Autocaliweb have a ReDoS vulnerability
summary: Calibre Web and Autocaliweb have a ReDoS vulnerability
severity: high
vendor: calibreweb
product: calibreweb
ecosystem: pip
affected:
  - calibreweb <= 0.6.24
published: '2025-07-24'
updated: '2026-07-07'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-2g7m-ph9x-7q7m'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-6998'
  - url: 'https://fluidattacks.com/advisories/megadeth'
  - url: 'https://github.com/gelbphoenix/autocaliweb'
  - url: 'https://github.com/janeczku/calibre-web'
tags:
  - osv
  - pip
  - exploit-available
epss: 0.00841
epssPercentile: 0.56102
ingestedAt: '2026-07-08T18:25:44.229Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/mind2hex/CVE-2025-6998-CalibreWeb-0.6.24-ReDoS'
  checkedAt: '2026-09-26T09:05:34.758Z'
exploitAvailable: true
---

## Overview

ReDoS in strip_whitespaces() function in cps/string_helper.py in Calibre Web and Autocaliweb allows unauthenticated remote attackers to cause denial of service via specially crafted username parameter that triggers catastrophic backtracking during login. This issue affects Calibre Web: 0.6.24 (Nicolette); Autocaliweb: from 0.7.0 before 0.7.1.

## Affected packages

- `calibreweb <= 0.6.24`

## Remediation

Refer to the advisory for the patched release.