CVE-2021-41168

Snudown is a reddit-specific fork of the Sundown Markdown parser used by GitHub, with Python integration added. In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown ` [reference_name]: https://www.example.com` are inserted into a hash table which was found to have a weak hash function, meaning that an attacker can reliably generate a large number of collisions for it. This makes the hash table vulnerable to a hash-collision DoS attack, a type of algorithmic complexity attack. Further the hash table allowed for duplicate entries resulting in long retrieval times. Proofs of concept and further discussion of the hash collision issue are discussed on the snudown GHSA(https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6). Users are advised to update to version 1.7.0.

Snudown is a reddit-specific fork of the Sundown Markdown parser used by GitHub, with Python integration added. In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown ` [reference_name]: https://www.example.com` are inserted into a hash table which was found to have a weak hash function, meaning that an attacker can reliably generate a large number of collisions for it. This makes the hash table vulnerable to a hash-collision DoS attack, a type of algorithmic complexity attack. Further the hash table allowed for duplicate entries resulting in long retrieval times. Proofs of concept and further discussion of the hash collision issue are discussed on the snudown GHSA(https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6). Users are advised to update to version 1.7.0.

Snudown es una bifurcación específica de reddit del parser Sundown Markdown usado por GitHub, con integración de Python añadida. En las versiones afectadas se ha detectado que snudown es vulnerable a ataques de denegación de servicio a su implementación de tabla de referencias. Las referencias escritas en markdown "[reference_name]: https://www.example.com" se insertan en una tabla hash que es encontrada que presenta una función hash débil, lo que significa que un atacante puede generar de forma fiable un gran número de colisiones para ella. Esto hace que la tabla hash sea vulnerable a un ataque DoS de colisiones hash, un tipo de ataque de complejidad algorítmica. Además, la tabla hash permitía entradas duplicadas, resultando en largos tiempos de recuperación. Las pruebas de concepto y una mayor discusión sobre el problema de la colisión de hash se discuten en el snudown GHSA(https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6). Se recomienda a usuarios que actualicen a la versión 1.7.0