CVE-2020-6817

Aliases:GHSA-vqhp-cxgc-6wmmPYSEC-2020-340SNYK-PYTHON-BLEACH-561754
Advisory lineage Upstream: 0 Downstream: 8
Modified
Published: 16 Feb 2023, 00:00
Last modified:19 Mar 2025, 15:21

Vulnerability Summary

Overall Risk (default)
medium
40/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
0.58% LOW
1% probability +0.40%
KEV
Not listed
Ransomware
No reports
Public exploits
1 found
Dark Web
Not detected

Timeline

16 Feb 2023, 00:00
Published
Vulnerability first disclosed
19 Mar 2025, 15:21
Last Modified
Vulnerability information updated

Description

bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS). Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).

CVSS Metrics

  • v4.0•HIGH•Score: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.58%• Percentile: 69%

Techniques & Countermeasures

  • CWE-1333•Inefficient Regular Expression Complexity

    The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

Affected Systems

  • mozilla•bleach

    < 3.1.4

  • mozilla•mozilla bleach

    ≥ unspecified, < 3.1.4

  • PyPI•bleach

    < 3.1.4

References (8)