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7.5
HIGH CVSS 3.1
CVE-2020-6817
Adobe Bleach Regular Expression Denial of Service
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']}).

INFO

Published Date :

Feb. 16, 2023, 10:15 p.m.

Last Modified :

March 19, 2025, 4:15 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2020-6817 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Mozilla bleach
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH [email protected]
CVSS 3.1 HIGH 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
The python-bleach package is affected by a regular expression denial of service vulnerability.
  • Update the affected python-bleach package.
  • Upgrade the affected packages.
Public PoC/Exploit Available at Github

CVE-2020-6817 has a 2 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2020-6817.

URL Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=1623633 Exploit Issue Tracking
https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1623633 Exploit Issue Tracking
https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2020-6817 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2020-6817 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
RonenDabach/-python-tda-bug-hunt-new

None

Updated: 2 years, 10 months ago
0 stars 0 fork 0 watcher
Born at : Dec. 15, 2022, 9:40 a.m. This repo has been linked 4 different CVEs too.
Profile Photo
engn33r/awesome-redos-security

List of RegEx DoS (ReDoS) CVEs and resources

security awesome redos regex dos regex-dos pentesting awesome-list regex-security

Updated: 8 months, 2 weeks ago
27 stars 3 fork 3 watcher
Born at : June 10, 2021, 1:57 a.m. This repo has been linked 76 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2020-6817 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2020-6817 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Mar. 19, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-1333
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=1623633
    Added Reference https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Initial Analysis by [email protected]

    Feb. 28, 2023

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://bugzilla.mozilla.org/show_bug.cgi?id=1623633 No Types Assigned https://bugzilla.mozilla.org/show_bug.cgi?id=1623633 Exploit, Issue Tracking
    Changed Reference Type https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm No Types Assigned https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm Vendor Advisory
    Added CWE NIST CWE-1333
    Added CPE Configuration OR *cpe:2.3:a:mozilla:bleach:*:*:*:*:*:*:*:* versions up to (excluding) 3.1.4
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 7.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.17 }} -0.34%

score

0.34466

percentile