Debian Security Advisory

DLA-2776-1 apache2 -- LTS security update

Date Reported:
02 Oct 2021
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2021-34798, CVE-2021-39275, CVE-2021-40438.
More information:

Several vulnerabilities were discovered in the Apache HTTP server. An attacker could send proxied requests to arbitrary servers, corrupt memory in some setups involving third-party modules, and cause the server to crash.

  • CVE-2021-34798

    Malformed requests may cause the server to dereference a NULL pointer.

  • CVE-2021-39275

    ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party / external modules may.

  • CVE-2021-40438

    A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user.

For Debian 9 stretch, these problems have been fixed in version 2.4.25-3+deb9u11.

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: