Impact:
Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches:
Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.

Workarounds:
Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

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Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-940
References
Metrics threat_severity

None

threat_severity

Low


Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
Description Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
Title undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse
Weaknesses CWE-367
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-06-17T18:30:26.429Z

Reserved: 2026-04-20T22:44:32.835Z

Link: CVE-2026-6733

cve-icon Vulnrichment

Updated: 2026-06-17T18:30:16.063Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Low

Publid Date: 2026-06-17T17:14:50Z

Links: CVE-2026-6733 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses