Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression
Description
The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive.
The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.
Impact
- Remote denial of service against any Node.js application using undici's WebSocket client
- A single compressed WebSocket frame of ~6 MB can decompress to ~1 GB or more
- Memory exhaustion occurs in native/external memory, bypassing V8 heap limits
- No application-level mitigation is possible as decompression occurs before message delivery
Patches
Users should upgrade to fixed versions.
Workarounds
No workaround are possible.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de npm | undici | < 6.24.0, >= 7.0.0, < 7.24.0 | 6.24.0, 7.24.0 |
Referencias
- https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q
- https://nvd.nist.gov/vuln/detail/CVE-2026-1526
- https://hackerone.com/reports/3481206
- https://cna.openjsf.org/security-advisories.html
- https://datatracker.ietf.org/doc/html/rfc7692
- https://github.com/nodejs/undici
- https://owasp.org/www-community/attacks/Denial_of_Service
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-409- Plataforma
- npm
- Paquete
undici- Publicada
- 13.03.2026
- Actualizado
- 11.10.2026 10:22
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-vrm6-8vpv-qv8q - CC BY 4.0
Historial de vulnerabilidades: undici
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
- 46
- Primera → última
- 06.2022 09.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 13
- Media 21
- Baja 12
Divulgaciones por año
- 2022: 5
- 2023: 3
- 2024: 5
- 2025: 2
- 2026: 31
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Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression esta entrada
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