{"id":"CVE-2020-6817","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-6817","generatedAt":"2026-10-28T01:51:41.931Z","title":"bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS).","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']}).","published":"2023-02-16T22:15:11.000Z","lastModified":"2026-06-17T03:23:52.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-1333"],"affected":["mozilla/bleach"],"epss":{"score":0.00718,"percentile":0.53596,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.72%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1623633","tags":["Exploit","Issue Tracking"],"source":"security@mozilla.org"},{"url":"https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1623633","tags":["Exploit","Issue Tracking"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-6817","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}