Debian Security Advisory

DLA-3401-1 apache2 -- LTS security update

Date Reported:
24 Apr 2023
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 1032476.
In Mitre's CVE dictionary: CVE-2023-25690, CVE-2023-27522.
More information:

Several vulnerabilities have been discovered in apache2, a webserver that may be used as front-end proxy for other applications. These vulnerabilities may lead to HTTP request smuggling, and thus to front-end security controls being bypassed.

Unfortunately, fixing these security vulnerabilities may require changes to configuration files. Some out-of-specification RewriteRule directives that were previously silently accepted, are now rejected with error AH10409. For instance, some RewriteRules that included a back-reference and the flags "[L,NC]" will need to be written with extra escaping flags such as "[B= ?,BNP,QSA]".

  • CVE-2023-25690

    Some mod_proxy configurations allow an HTTP request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution.

  • CVE-2023-27522

    HTTP Response Smuggling in mod_proxy_uwsgi

For Debian 10 buster, these problems have been fixed in version 2.4.38-3+deb10u10.

We recommend that you upgrade your apache2 packages.

For the detailed security status of apache2 please refer to its security tracker page at:

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: