7.5
HIGH
CVE-2021-33503
Apache HTTP Server URL Parsing Denial of Service
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.

INFO

Published Date :

June 29, 2021, 11:15 a.m.

Last Modified :

Nov. 21, 2024, 6:08 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

3.9
Public PoC/Exploit Available at Github

CVE-2021-33503 has a 4 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-33503 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Oracle zfs_storage_appliance_kit
2 Oracle enterprise_manager_ops_center
3 Oracle instantis_enterprisetrack
1 Fedoraproject fedora
1 Python urllib3
: Total Affected Vendor : 3 | Products : 5
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-33503.

URL Resource
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg Third Party Advisory
https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec Patch Third Party Advisory
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 Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg Third Party Advisory
https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec Patch Third Party Advisory
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 Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
elliotsecops/VulnGuard

Minimalist vulnerability scanner designed to help developers identify and mitigate security vulnerabilities in their projects.

cybersecurity cybersecurity-engineering ethical-hacking pentesting security-audit

Python

Updated: 2 months ago
2 stars 0 fork 0 watcher
Born at : Sept. 28, 2024, 2:36 a.m. This repo has been linked 2 different CVEs too.
Profile Photo
HotDB-Community/HotDB-Engine

None

CMake Shell Perl C++ C Batchfile CSS Makefile M4 Python

Updated: 9 months, 3 weeks ago
34 stars 0 fork 0 watcher
Born at : Feb. 1, 2024, 11:43 a.m. This repo has been linked 71 different CVEs too.
Profile Photo
p-rog/cve-analyser

A tool to analyse the list of detected CVEs in the containers (usually created by static security scanner) and compare them to the Red Hat Security Data.

security openshift

Go Makefile

Updated: 3 months, 3 weeks ago
21 stars 3 fork 3 watcher
Born at : Nov. 3, 2021, 8:36 p.m. This repo has been linked 4 different CVEs too.
Profile Photo
engn33r/awesome-redos-security

List of RegEx DoS (ReDoS) CVEs and resources

security awesome redos regex dos regex-dos pentesting awesome-list regex-security

Updated: 2 months, 2 weeks ago
24 stars 2 fork 2 watcher
Born at : June 10, 2021, 1:57 a.m. This repo has been linked 76 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-33503 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-33503 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://github.com/advisories/GHSA-q2q7-5pp4-w6pg
    Added Reference https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/
    Added Reference https://security.gentoo.org/glsa/202107-36
    Added Reference https://www.oracle.com/security-alerts/cpuoct2021.html
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/ [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/ [No types assigned]
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
  • Reanalysis by [email protected]

    Aug. 24, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions up to (excluding) 1.25.4 *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions from (including) 1.26.0 up to (excluding) 1.26.5 OR *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions from (including) 1.25.4 up to (excluding) 1.26.5
  • Reanalysis by [email protected]

    Jan. 24, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions up to (excluding) 1.26.5 OR *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions up to (excluding) 1.25.4 *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions from (including) 1.26.0 up to (excluding) 1.26.5
  • Modified Analysis by [email protected]

    Dec. 08, 2021

    Action Type Old Value New Value
    Changed Reference Type https://www.oracle.com/security-alerts/cpuoct2021.html No Types Assigned https://www.oracle.com/security-alerts/cpuoct2021.html Patch, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:* *cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:* *cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:* *cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Oct. 20, 2021

    Action Type Old Value New Value
    Added Reference https://www.oracle.com/security-alerts/cpuoct2021.html [No Types Assigned]
  • Modified Analysis by [email protected]

    Sep. 14, 2021

    Action Type Old Value New Value
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/ Mailing List, Third Party Advisory
    Changed Reference Type https://security.gentoo.org/glsa/202107-36 No Types Assigned https://security.gentoo.org/glsa/202107-36 Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Jul. 15, 2021

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/202107-36 [No Types Assigned]
  • CVE Modified by [email protected]

    Jul. 08, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/ [No Types Assigned]
  • CVE Modified by [email protected]

    Jul. 04, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/ [No Types Assigned]
  • Initial Analysis by [email protected]

    Jul. 02, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://github.com/advisories/GHSA-q2q7-5pp4-w6pg No Types Assigned https://github.com/advisories/GHSA-q2q7-5pp4-w6pg Third Party Advisory
    Changed Reference Type https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec No Types Assigned https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec Patch, Third Party Advisory
    Added CWE NIST CWE-400
    Added CPE Configuration OR *cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:* versions up to (excluding) 1.26.5
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-33503 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-33503 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.44 }} 0.14%

score

0.74340

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: