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CVE-2018-20852

UnknownEPSS 3.88%

Last modified

CVE-2018-20852 is a vulnerability of currently unknown severity. http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). EPSS estimates a 3.88% chance of exploitation in the next 30 days.

Description

http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). When a program uses http.cookiejar.DefaultPolicy and tries to do an HTTP connection to an attacker-controlled server, existing cookies can be leaked to the attacker. This affects 2.x through 2.7.16, 3.x before 3.4.10, 3.5.x before 3.5.7, 3.6.x before 3.6.9, and 3.7.x before 3.7.3.

Metrics

EPSS Probability
3.88%

88.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
PythonPython>= 2.0, <= 2.7.16
PythonPython>= 3.0.0, < 3.4.10
PythonPython>= 3.5.0, < 3.5.7
PythonPython>= 3.6.0, < 3.6.9
PythonPython>= 3.7.0, < 3.7.3

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2018-20852?
http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). When a program uses http.cookiejar.DefaultPolicy and tries to do an HTTP connection to an attacker-controlled server, existing cookies can be leaked to the attacker. This affects 2.x through 2.7.16, 3.x before 3.4.10, 3.5.x before 3.5.7, 3.6.x before 3.6.9, and 3.7.x before 3.7.3.
How severe is CVE-2018-20852?
Severity scoring for CVE-2018-20852 is pending analysis. The EPSS model estimates a 3.88% probability of exploitation in the next 30 days.
How do I fix CVE-2018-20852?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-20852?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST