In PHP versions 8.1.* before 8.1.31, 8.2.* before 8.2.26, 8.3.* before 8.3.14, due to an error in convert.quoted-printable-decode filter certain data can lead to buffer overread by one byte, which can in certain circumstances lead to crashes or disclose content of other memory areas.
https://github.com/php/php-src/security/advisories/GHSA-r977-prxv-hc43