Vulnerability · Published Feb 16, 2023 · Assigned by mozilla
CVE-2020-6817
High 7.5
In plain English
A high-severity regular-expression denial of service in Mozilla Bleach from Mozilla. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.7%top 45.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official 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']}).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-bleach | 3.1.4-1 | DEBIAN-CVE-2020-6817 |
| Debian:13 | python-bleach | 3.1.4-1 | DEBIAN-CVE-2020-6817 |
| Debian:14 | python-bleach | 3.1.4-1 | DEBIAN-CVE-2020-6817 |
| PyPI | bleach | 3.1.4 | GHSA-vqhp-cxgc-6wmm |
| PyPI | bleach | 3.1.4 | PYSEC-2020-340 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Mozilla Bleach | unspecified – before 3.1.4 |
Weakness: CWE-1333 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H