CVE-2022-31129

moment is a JavaScript date library for parsing, validating, manipulating, and formatting dates. Affected versions of moment were found to use an inefficient parsing algorithm. Specifically using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs. Users may notice a noticeable slowdown is observed with inputs above 10k characters. Users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks. The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. Users are advised to upgrade. Users unable to upgrade should consider limiting date lengths accepted from user input.

moment is a JavaScript date library for parsing, validating, manipulating, and formatting dates. Affected versions of moment were found to use an inefficient parsing algorithm. Specifically using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs. Users may notice a noticeable slowdown is observed with inputs above 10k characters. Users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks. The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. Users are advised to upgrade. Users unable to upgrade should consider limiting date lengths accepted from user input.

### Impact * using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs * noticeable slowdown is observed with inputs above 10k characters * users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks ### Patches The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. ### Workarounds In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities. ### References There is an excellent writeup of the issue here: https://github.com/moment/moment/pull/6015#issuecomment-1152961973= ### Details The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. `moment("(".repeat(500000))` will take a few minutes to process, which is unacceptable.

### Impact * using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs * noticeable slowdown is observed with inputs above 10k characters * users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks ### Patches The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking. ### Workarounds In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities. ### References There is an excellent writeup of the issue here: https://github.com/moment/moment/pull/6015#issuecomment-1152961973= ### Details The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. `moment("(".repeat(500000))` will take a few minutes to process, which is unacceptable.

moment es una biblioteca de fechas en JavaScript para analizar, comprobar, manipular y formatear fechas. Se ha detectado que las versiones afectadas de moment usan un algoritmo de análisis sintáctico ineficiente. Concretamente, el análisis sintáctico de cadena a fecha en moment (más concretamente el análisis sintáctico rfc2822, que es intentado por defecto) presenta una complejidad cuadrática (N^2) en entradas específicas. Los usuarios pueden notar una notable ralentización con entradas de más de 10k caracteres. Los usuarios que pasan cadenas proporcionadas por el usuario sin comprobaciones de longitud de cordura al constructor del momento son vulnerables a ataques (Re)DoS. El problema está parcheado en versión 2.29.4, el parche puede aplicarse a todas las versiones afectadas con un mínimo ajuste. Es recomendado a usuarios actualicen. Los usuarios que no puedan actualizar deberían considerar la posibilidad de limitar la longitud de las fechas aceptadas por el usuario