CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2021-33503
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.
Severity
- EPSS
- 3.3% chance of exploitation in the next 30 days; higher than 88% of CVEs (scores of 2026-10-31)
- CWE
- CWE-400
- Published
- Modified
- Record from
- the NVD, synced
Affected
- fedoraproject:fedora
- oracle:enterprise_manager_ops_center
- oracle:instantis_enterprisetrack
- oracle:zfs_storage_appliance_kit
- python:urllib3
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-q2q7-5pp4-w6pg | PyPI | urllib3 | >=1.25.4 <1.26.5 | 1.26.5 |
| PYSEC-2021-108 | PyPI | urllib3 | >=1.25.4 <1.26.5 | 1.26.5 |
References
- https://github.com/advisories/GHSA-q2q7-5pp4-w6pg
- https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/
- https://security.gentoo.org/glsa/202107-36