CVE-2026-1526

Aliases:GHSA-vrm6-8vpv-qv8q
Advisory lineage Upstream: 0 Downstream: 10
Analyzed
Published: 12 Mar 2026, 20:08
Last modified:15 Jul 2026, 01:21

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
1.15% LOW
1% probability +1.13%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

12 Mar 2026, 20:08
Published
Vulnerability first disclosed
15 Jul 2026, 01:21
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 1.15%• Percentile: 63%

Techniques & Countermeasures

  • CWE-409•Improper Handling of Highly Compressed Data (Data Amplification)

    The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

  • CWE-770•Allocation of Resources Without Limits or Throttling

    The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Affected Systems

  • nodejs•undici

    < 6.24.0 | ≥ 7.0.0, < 7.24.0

  • Npm•undici

    < 6.24.0 | ≥ 7.0.0, < 7.24.0

  • undici•undici

    < 6.24.0; 7.0.0 < 7.24.0

References (25)