CVE Watch15 jul 2026

CVE-2026-1526

The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompres

CVSS

7.5

Alto

EPSS

1.1%

p63

KEV

—

Exploit Today

0-100

Publicado: 12 mar 2026 · Última mod.: 15 jul 2026 · CWE-409 · CWE-770

EPSS · 30d

1.1%EPSS · 30 días1.1%

2026-06-302026-07-16

Descripción técnica

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.

Referencias oficiales

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