CVE-2021-33503

Description

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.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.94% Top 25%
Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory gentoo.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/ vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/ vendor advisory
https://security.gentoo.org/glsa/202107-36 third party advisory vendor advisory
https://www.oracle.com/security-alerts/cpuoct2021.html third party advisory patch
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg third party advisory
https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-33503?
CVE-2021-33503 has been scored as a high severity vulnerability.
How to fix CVE-2021-33503?
To fix CVE-2021-33503, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-33503 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-33503 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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