High severity · published Jun 29, 2021
CVE-2021-33503
An issue was discovered in urllib3 before 1.26.5
7.5
CVSS
3.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.3% · higher than 88% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EM
Enterprise Manager Ops Center · Oracle
12.4.0.0 · source: NVD
FE
Fedora · Fedoraproject
33; 34 · source: NVD
IE
Instantis Enterprisetrack · Oracle
17.1; 17.2; 17.3 · source: NVD
UR
Urllib3 · Python
1.25.4 before 1.26.5 · source: NVD
ZS
Zfs Storage Appliance Kit · Oracle
8.8 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-33503
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-33503
Third Party Advisory
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg
Patch
https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/
Third Party Advisory
https://security.gentoo.org/glsa/202107-36
Patch
https://www.oracle.com/security-alerts/cpuoct2021.html
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