---
id: CVE-2021-4171
aliases:
  - GHSA-xp7p-3gx7-j6wx
  - PYSEC-2026-307
title: calibre-web is vulnerable to Business Logic Errors
summary: calibre-web is vulnerable to Business Logic Errors
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: calibreweb
product: calibreweb
ecosystem: pip
affected:
  - calibreweb < 0.6.15
patched:
  - calibreweb 0.6.15
published: '2022-01-21'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T16:30:05.977964866Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-xp7p-3gx7-j6wx'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-4171'
  - url: >-
      https://github.com/janeczku/calibre-web/commit/3e0d8763c377d2146462811e3e4ccf13f0d312ce
  - url: 'https://github.com/janeczku/calibre-web'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/calibreweb/PYSEC-2026-307.yaml
  - url: 'https://huntr.dev/bounties/1117f439-133c-4563-afb2-6cd80607bd5c'
  - url: 'https://pypi.org/project/calibreweb'
  - url: 'https://github.com/advisories/GHSA-xp7p-3gx7-j6wx'
tags:
  - osv
  - pip
  - ghsa
epss: 0.01387
epssPercentile: 0.72103
ingestedAt: '2026-10-27T16:32:34.372Z'
---

## Overview

calibre-web is vulnerable to Business Logic Errors

## Affected packages

- `calibreweb < 0.6.15`

## Remediation

Upgrade to a patched release:

- `calibreweb 0.6.15`