USN-4994-2: Apache HTTP Server vulnerabilities

21 June 2021

Several security issues were fixed in Apache HTTP Server.

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Details

USN-4994-1 fixed several vulnerabilities in Apache. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.

Original advisory details:

Antonio Morales discovered that the Apache mod_auth_digest module
incorrectly handled certain Digest nonces. A remote attacker could possibly
use this issue to cause Apache to crash, resulting in a denial of service.
(CVE-2020-35452)

Antonio Morales discovered that the Apache mod_session module incorrectly
handled certain Cookie headers. A remote attacker could possibly use this
issue to cause Apache to crash, resulting in a denial of service.
(CVE-2021-26690)

Christophe Jaillet discovered that the Apache mod_session module
incorrectly handled certain SessionHeader values. A remote attacker could
use this issue to cause Apache to crash, resulting in a denial of service,
or possibly execute arbitrary code. (CVE-2021-26691)

Christoph Anton Mitterer discovered that the new MergeSlashes configuration
option resulted in unexpected behaviour in certain situations.
(CVE-2021-30641)

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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Update instructions

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

Ubuntu 16.04
Ubuntu 14.04

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

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