fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option. References: https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-6w63-h3fj-q4vw https://github.com/NaturalIntelligence/fast-xml-parser/commit/39b0e050bb909e8499478657f84a3076e39ce76c
This issue has been addressed in the following products: MTA-6.2-RHEL-9 MTA-6.2-RHEL-8 Via RHSA-2023:4627 https://access.redhat.com/errata/RHSA-2023:4627
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2023-34104