A PHP security update has been released for Ubuntu Linux 16.04 ESM.

USN-6053-1: PHP vulnerability

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Ubuntu Security Notice USN-6053-1
May 02, 2023

php7.0 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

PHP could be made to bypass password checking if a specially crafted input was
provided.

Software Description:
- php7.0: HTML-embedded scripting language interpreter

Details:

It was discovered that PHP incorrectly handled certain invalid Blowfish
password hashes. An invalid password hash could possibly allow applications to
accept any password as valid, contrary to expectations.

Update instructions:

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

Ubuntu 16.04 ESM:
libapache2-mod-php7.0 7.0.33-0ubuntu0.16.04.16+esm6
php7.0 7.0.33-0ubuntu0.16.04.16+esm6
php7.0-cgi 7.0.33-0ubuntu0.16.04.16+esm6
php7.0-cli 7.0.33-0ubuntu0.16.04.16+esm6
php7.0-fpm 7.0.33-0ubuntu0.16.04.16+esm6

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

References:
https://ubuntu.com/security/notices/USN-6053-1
CVE-2023-0567