CVE-2021-44686

HIGH
Published Dec 7, 20214y ago · Modified Jun 17, 20262w ago
7.5 CVSS 3.1
High
Find Similar
Published Dec 7, 2021 4y ago
Last Modified Jun 17, 2026 2w ago

Description

calibre before 5.32.0 contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in html_preprocess_rules in ebooks/conversion/preprocess.py.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-400 Uncontrolled Resource Consumption Resource Mgmt

Affected Products 2

VendorProductVersionRange
calibre-ebookcalibre* <5.32.0
fedoraprojectfedora34any

References 5

  • bugs.launchpad.net https://bugs.launchpad.net/calibre/+bug/1951979
    ExploitIssue TrackingVendor Advisory
  • github.com https://github.com/dwisiswant0/advisory/issues/18
    ExploitIssue TrackingPatchThird Party Advisory
  • github.com https://github.com/kovidgoyal/calibre/compare/v5.31.1...v5.32.0
    PatchThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2024/09/msg00005.html
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W7QKFPYJ23KG6WJ5NIYAM4N2NWZCLQGL/

Remediation

  • github.com https://github.com/dwisiswant0/advisory/issues/18
    ExploitIssue TrackingPatchThird Party Advisory
  • github.com https://github.com/kovidgoyal/calibre/compare/v5.31.1...v5.32.0
    PatchThird Party Advisory