SB2026101488 - Uncaught Exception in undici

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Main Vulnerability Database SB2026101488

SB2026101488 - Uncaught Exception in undici

Published: October 14, 2026

Security Bulletin ID SB2026101488
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Uncaught Exception (CVE-ID: CVE-2026-109855)

CWE-ID: CWE-248 - Uncaught Exception

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an uncaught exception in undici's experimental WebSocket client when handling a failed WebSocket handshake over HTTP/2. A remote attacker can return a response that fails handshake validation from a malicious server and then destroy the connection to cause a denial of service.

Exploitation requires the client to connect to the malicious server with HTTP/2 support enabled through allowH2: true, which is the default setting.


Remediation

Install update from vendor's website.

References