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CVE-2022-21195

ReDoS vulnerability in all 'url-regex' package versions.

  • CVSS 7.5
  • CWE-1333
  • Input Validation and Sanitization
  • Remote

All versions of package url-regex are vulnerable to Regular Expression Denial of Service (ReDoS) which can cause the CPU usage to crash.

CVE
CVE-2022-21195
CWE
CWE-1333
CVSS base score
7.5
Published
2022-05-20
OWASP
A06 Vulnerable and Outdated Components
Orthogonal defect classification
Function
Code defect classification
Incorrect Functionality
Category
Input Validation and Sanitization
Subcategory
Command Injection
Accessibility scope
Remote
Impact
Denial of Service (DoS)
Fixed by upgrading
Yes

Solution

Update url-regex to a non-vulnerable version.

Vulnerable code sample

import re

url_pattern = re.compile(
    r'^(https?://)?(www\.)?([a-zA-Z0-9-]+\.)+[a-zA-Z]{2,6}(/[^\s]*)?$'
)

def is_valid_url(url):
    # VULNERABLE: This code is susceptible to sql injection
    return bool(url_pattern.match(url))

test_urls = [
    "http://example.com",
    "https://www.example.com",
    "www.example.com",
    "example.com",
    "http://example.com/path/to/resource?query=1&other_query=2",
    "http://example.com/" + "a" * 1000 + ".com"
]

for url in test_urls:
    print(f"{url}: {is_valid_url(url)}")

Patched code sample

import re

url_pattern = re.compile(
    r'(?:(?:https?://|www\.)[^\s/$.?#].[^\s]*)',
    re.IGNORECASE
)

def is_valid_url(url):
    # SECURE: This version prevents sql injection
    return bool(url_pattern.match(url))

test_urls = [
    "http://example.com",
    "https://www.example.com",
    "www.example.com",
    "example.com",
    "http://example.com/path/to/resource?query=1&other_query=2",
    "http://example.com/" + "a" * 1000 + ".com"
]

for url in test_urls:
    print(f"{url}: {is_valid_url(url)}")

Cite this entry

@misc{vaitp:cve202221195,
  title        = {{ReDoS vulnerability in all 'url-regex' package versions.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2022},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2022-21195},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2022-21195/}}
}
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