Parse Server has Regular Expression Denial of Service (ReDoS) via `$regex` query in LiveQuery
Impact
A malicious client can subscribe to a LiveQuery with a crafted $regex pattern that causes catastrophic backtracking, blocking the Node.js event loop. This makes the entire Parse Server unresponsive, affecting all clients. Any Parse Server deployment with LiveQuery enabled is affected. The attacker only needs the application ID and JavaScript key, both of which are public in client-side apps.
This only affects LiveQuery subscription matching, which evaluates regex in JavaScript on the Node.js event loop. Normal REST and GraphQL queries are not affected because their regex is evaluated by the database engine.
Patches
Regex evaluation in LiveQuery subscription matching now runs in an isolated VM context with a configurable timeout via a new Parse Server option `liveQuery.regexTimeout, with defaults 100 ms. A regex that exceeds the timeout is treated as non-matching.
The protection adds approximately 50 microseconds of overhead per regex evaluation. For most applications this is negligible, but it can add up if there is a very large number of LiveQuery subscriptions that use $regex on the same class. For example, 10,000 concurrent regex subscriptions would add approximately 500ms of processing time per object save event on that class. Set liveQuery.regexTimeout: 0 to disable the protection and use native regex evaluation without overhead.
Workarounds
Use the beforeSubscribe Cloud Code hook to reject any LiveQuery subscription that contains a $regex operator. Note that this also blocks the LiveQuery startsWith, endsWith, and contains query methods, as they use $regex internally.
// Repeat for each class that is used with LiveQuery
Parse.Cloud.beforeSubscribe('MyClass', request => {
const where = request.query._where || {};
for (const value of Object.values(where)) {
if (value?.$regex) {
throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, '$regex not allowed in LiveQuery subscriptions');
}
}
});References
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-mf3j-86qx-cq5j
- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.14
- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.11
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de npm | parse-server | >= 9.0.0-alpha.1, < 9.5.0-alpha.14, < 8.6.11 | 9.5.0-alpha.14, 8.6.11 |
Referencias
- https://github.com/parse-community/parse-server/security/advisories/GHSA-mf3j-86qx-cq5j
- https://nvd.nist.gov/vuln/detail/CVE-2026-30925
- https://github.com/parse-community/parse-server
- https://github.com/parse-community/parse-server/releases/tag/8.6.11
- https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.14
- Vector CVSS
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Debilidad (CWE)
CWE-1333- Plataforma
- npm
- Paquete
parse-server- Publicada
- 10.03.2026
- Actualizado
- 11.10.2026 10:22
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-mf3j-86qx-cq5j - CC BY 4.0
Historial de vulnerabilidades: parse-server
Todas las vulnerabilidades publicadas de este paquete (Paquete de npm), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 116
- Primera → última
- 06.2019 06.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Crítica 17
- Alta 49
- Media 40
- Baja 10
Divulgaciones por año
- 2019: 2
- 2020: 4
- 2021: 4
- 2022: 12
- 2023: 5
- 2024: 4
- 2025: 6
- 2026: 79
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