Cyber Resilience

CVE-2020-6817

HighPublic PoC

Published: 16 February 2023

Published
16 February 2023
Modified
19 March 2025
KEV Added
—
Patch
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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0058 69.4th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2020-6817 is a high-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Mozilla Bleach. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 30.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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']}).

CWE(s)
CWE-1333

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mozilla
bleach
≤ 3.1.4

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References