CVE-2026-12151

Aliases:GHSA-vxpw-j846-p89q
Advisory lineage Upstream: 0 Downstream: 18
PUBLISHED
Published: 17 Jun 2026, 16:05
Last modified:21 Jul 2026, 12:05

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
0.61% LOW
1% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

17 Jun 2026, 16:05
Published
Vulnerability first disclosed
21 Jul 2026, 12:05
Last Modified
Vulnerability information updated

Description

Impact: The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. Patches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.

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: 0.61%• Percentile: 45%

Techniques & Countermeasures

  • CWE-400•Uncontrolled Resource Consumption

    The product does not properly control the allocation and maintenance of a limited resource.

  • 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

  • Npm•undici

    < 6.27.0 | ≥ 7.0.0, < 7.28.0 | ≥ 8.0.0, < 8.5.0

  • undici•undici

    < 6.26.0 | ≥ 7.0.0, < 7.28.0 | ≥ 8.0.0, < 8.5.0

References (21)