USN-6885-4: Apache HTTP Server regression

Publication date

7 April 2025

Overview

USN-6885-1 introduced a regression in Apache HTTP Server.


Packages

Details

USN-6885-1 fixed a vulnerability in Apache. The patch
for CVE-2024-38474 was incomplete and caused regressions.
This update provides the fix for that issue.

Original advisory details:

Orange Tsai discovered that the Apache HTTP Server mod_rewrite module
incorrectly handled certain substitutions. A remote attacker could
possibly use this issue to execute scripts in directories not directly
reachable by any URL, or cause a denial of service. Some environments
may require using the new UnsafeAllow3F flag to handle unsafe
substitutions. (CVE-2024-38474)

USN-6885-1 fixed a vulnerability in Apache. The patch
for CVE-2024-38474 was incomplete and caused regressions.
This update provides the fix for that issue.

Original advisory details:

Orange Tsai discovered that the Apache HTTP Server mod_rewrite module
incorrectly handled certain substitutions. A remote attacker could
possibly use this issue to execute scripts in directories not directly
reachable by any URL, or cause a denial of service. Some environments
may require using the new UnsafeAllow3F flag to handle unsafe
substitutions. (CVE-2024-38474)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
24.10 oracular apache2 –  2.4.62-1ubuntu1.1
24.04 noble apache2 –  2.4.58-1ubuntu8.6
22.04 jammy apache2 –  2.4.52-1ubuntu4.14
20.04 focal apache2 –  2.4.41-4ubuntu3.23
18.04 bionic apache2 –  2.4.29-1ubuntu4.27+esm4  
16.04 xenial apache2 –  2.4.18-2ubuntu3.17+esm14  

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