CVE-2026-63718
Description
A flaw was found in the mod_proxy_uwsgi module of Apache HTTP Server. This issue allows HTTP response smuggling when the server processes a crafted uWSGI response containing a Transfer-Encoding header. A remote attacker can exploit this vulnerability to desynchronize HTTP communications, potentially leading to response tampering or cache poisoning for other users.
Mitigation
If uWSGI proxy functionality is not required, disable the mod_proxy_uwsgi module:
1. Edit the Apache proxy module configuration file (typically `/etc/httpd/conf.modules.d/00-proxy.conf`) and comment out the loading directive:
# LoadModule proxy_uwsgi_module modules/mod_proxy_uwsgi.so
2. Restart the Apache HTTP Server daemon:
systemctl restart httpd
Warning: Restarting the httpd service causes an immediate disruption to active client connections. Disabling this module will prevent the server from handling requests routed through the uWSGI protocol.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Understanding the Weakness (CWE)
Integrity,Non-Repudiation,Access Control
Technical Impact: Unexpected State; Hide Activities; Bypass Protection Mechanism
An attacker could create HTTP messages to exploit a number of weaknesses including 1) the message can trick the web server to associate a URL with another URL's webpage and caching the contents of the webpage (web cache poisoning attack), 2) the message can be structured to bypass the firewall protection mechanisms and gain unauthorized access to a web application, and 3) the message can invoke a script or a page that returns client credentials (similar to a Cross Site Scripting attack).
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