PT-2020-19243 · Mozilla+3 · Bleach+3

Schwag09 · Published 2020-03-30 · Updated 2026-03-05 · CVE-2020-6817

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions Bleach versions prior to 3.1.4

Description The 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']}).

Recommendations For versions prior to 3.1.4, update to version 3.1.4 to resolve the issue. As a temporary workaround, consider not whitelisting the style attribute in bleach.clean calls. Additionally, limit input string length to minimize the risk of exploitation.

Exploit

Fix

DoS

Resource Exhaustion

Weakness Enumeration

CWE-1333

CWE-400

Related Identifiers

CVE-2020-6817

DLA-2167-1

GHSA-VQHP-CXGC-6WMM

MGASA-2020-0176

OPENSUSE-SU-2021:0552-1

OPENSUSE-SU-2021:0571-1

OPENSUSE-SU-2021_0552-1

OPENSUSE-SU-2024:11219-1

OPENSUSE-SU-2024:14134-1

PYSEC-2020-340

SNYK-PYTHON-BLEACH-561754

USN-8077-1

Affected Products

Bleach

Linuxmint

Suse

Ubuntu

References · 46

• 🔥 https://bugzilla.mozilla.org/show_bug.cgi?id=1623633 · Exploit
• https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2020-6817 · Vendor Advisory
• https://osv.dev/vulnerability/USN-8077-1 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-vqhp-cxgc-6wmm · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2020-6817 · Security Note
• https://osv.dev/vulnerability/MGASA-2020-0176 · Vendor Advisory
• https://osv.dev/vulnerability/DLA-2167-1 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2021:0552-1 · Vendor Advisory
• https://osv.dev/vulnerability/PYSEC-2020-340 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2021:0571-1 · Vendor Advisory
• https://debian.org/security/2020/dsa-4643 · Vendor Advisory
• https://ubuntu.com/security/CVE-2020-6816 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2020-6817 · Security Note
• https://ubuntu.com/security/CVE-2021-23980 · Vendor Advisory