Vulnerability Details : CVE-2020-6817
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']}).
Vulnerability category: Denial of service
Products affected by CVE-2020-6817
- cpe:2.3:a:mozilla:bleach:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2020-6817
0.08%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 35 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2020-6817
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
7.5
|
HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
3.9
|
3.6
|
NIST |
CWE ids for CVE-2020-6817
-
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.Assigned by: nvd@nist.gov (Primary)
References for CVE-2020-6817
-
https://bugzilla.mozilla.org/show_bug.cgi?id=1623633
1623633 - (CVE-2020-6817) Regular expression denial-of-service in mozilla/bleach BleachSanitizerFilter.sanitize_css gauntlet regular expressionExploit;Issue Tracking
-
https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm
regular expression denial-of-service (ReDoS) in BleachSanitizerFilter.sanitize_css gauntlet regular expression · Advisory · mozilla/bleach · GitHubVendor Advisory
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