CVE-2021-33503

moderate-risk
Published 2021-06-29

An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.

Do I need to act?

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0.86% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Vendors

43
/ 100
moderate-risk
Severity 26/34 · High
Exploitability 3/34 · Minimal
Exposure 14/34 · Moderate