Headline
GHSA-px8h-6qxv-m22q: Incorrect parsing of nameless cookies leads to __Host- cookies bypass
Browsers may allow “nameless” cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain.
Werkzeug <= 2.2.2 will parse the cookie =__Host-test=bad as __Host-test=bad. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key.
Package
pip Werkzeug (pip)
Affected versions
< 2.2.3
Patched versions
2.2.3
Description
Browsers may allow “nameless” cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain.
Werkzeug <= 2.2.2 will parse the cookie =__Host-test=bad as __Host-test=bad. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key.
References
- GHSA-px8h-6qxv-m22q
- https://nvd.nist.gov/vuln/detail/CVE-2023-23934
- pallets/werkzeug@cf275f4
- https://github.com/pallets/werkzeug/releases/tag/2.2.3
Reviewed
Feb 15, 2023
Published to the GitHub Advisory Database
Feb 15, 2023
Published by the National Vulnerability Database
Feb 14, 2023
davidism published to pallets/werkzeug
Feb 14, 2023
Related news
Debian Linux Security Advisory 5470-1 - Several vulnerabilities were discovered in python-werkzeug, a collection of utilities for WSGI applications.
Ubuntu Security Notice 5948-2 - USN-5948-1 fixed vulnerabilities in Werkzeug. This update provides the corresponding updates for Ubuntu 23.04. It was discovered that Werkzeug did not properly handle the parsing of nameless cookies. A remote attacker could possibly use this issue to shadow other cookies.
Vulnerability in the Oracle Java SE, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Hotspot). Supported versions that are affected are Oracle Java SE: 8u361, 8u361-perf, 11.0.18, 17.0.6; Oracle GraalVM Enterprise Edition: 20.3.9, 21.3.5 and 22.3.1. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle Java SE, Oracle GraalVM Enterprise Edition accessible data. Note: This vulnerability applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. This vulnerability can also be exploited by using APIs in the specified Component, e.g., through...
Ubuntu Security Notice 5948-1 - It was discovered that Werkzeug did not properly handle the parsing of nameless cookies. A remote attacker could possibly use this issue to shadow other cookies. It was discovered that Werkzeug could be made to process unlimited number of multipart form data parts. A remote attacker could possibly use this issue to cause Werkzeug to consume resources, leading to a denial of service.
Werkzeug is a comprehensive WSGI web application library. Browsers may allow "nameless" cookies that look like `=value` instead of `key=value`. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like `=__Host-test=bad` for another subdomain. Werkzeug prior to 2.2.3 will parse the cookie `=__Host-test=bad` as __Host-test=bad`. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key. The issue is fixed in Werkzeug 2.2.3.