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Catastrophic backtracking in URL authority parser when passed URL containing many @ characters

Moderate
sethmlarson published GHSA-q2q7-5pp4-w6pg May 26, 2021

Package

pip urllib3 (pip)

Affected versions

<1.26.5

Patched versions

>=1.26.5

Description

Impact

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.

Patches

The issue has been fixed in urllib3 v1.26.5.

References

For more information

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Severity

Moderate

CVE ID

CVE-2021-33503

Weaknesses

No CWEs

Credits