CVE-2023-27522: uwsgi Package Vulnerability in Apache HTTP Server Leading to HTTP Response Smuggling
Summary
CVE-2023-27522: Apache HTTP Server via mod_proxy_uwsgi HTTP response smuggling. Affects uwsgi versions < 2.0.22. Fixed in 2.0.22. How to fix ↓
Also tracked for
The same CVE-2023-27522 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
The uwsgi package is a popular application server interface for hosting Python web applications. It facilitates communication between web servers and Python applications, enabling efficient request handling and response generation. However, certain versions of uwsgi are vulnerable to an HTTP Response Smuggling attack when used with Apache HTTP Server, specifically versions 2.4.30 through 2.4.55. This vulnerability arises from improper handling of special characters in the origin response header, which can lead to truncated or split responses forwarded to clients.
Vulnerability Detail
The vulnerability identified as CVE-2023-27522 allows for HTTP Response Smuggling in Apache HTTP Server through the mod_proxy_uwsgi module. This issue affects Apache HTTP Server versions 2.4.30 to 2.4.55 and the uwsgi package prior to version 2.0.22. Attackers can exploit this vulnerability by crafting responses with special characters that manipulate how the server processes and forwards responses to clients, potentially leading to unauthorized access to sensitive information or other malicious outcomes.
How To Fix
Latest published version: 2.0.31 as of 23 Oct 2026
pip install --upgrade "uwsgi==2.0.31"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.0.22
This is the first release that contains the fix.
pip install --upgrade "uwsgi==2.0.22"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate patching is not feasible, consider implementing a reverse proxy configuration that does not rely on mod_proxy_uwsgi, or sanitize the origin response headers to eliminate special characters that could lead to exploitation.
Conclusion
CVE-2023-27522 represents a significant security risk for applications using the uwsgi package with Apache HTTP Server. It is crucial to update to the patched version of uwsgi and ensure that your server is running a secure version to protect against potential exploitation.
See every vulnerability recorded for uwsgi →
FAQ
CVE-2023-27522 is a vulnerability in the uwsgi package that affects Apache HTTP Server, allowing for HTTP Response Smuggling due to improper handling of response headers.
The vulnerability affects all versions of uwsgi prior to 2.0.22.
Exploitation of this vulnerability can lead to unauthorized access to sensitive information, data manipulation, or other malicious activities.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score for CVE-2023-27522 is 7.5, indicating a high severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for uwsgi.
