CVE-2026-6733 (LOW): detected in Lambda Docker Images.

[the-lambda-watchdog]

CVE Details

CVE ID	Severity	Affected Package	Installed Version	Fixed Version	Date Published	Date of Scan
CVE-2026-6733	LOW	undici	6.25.0	6.27.0, 7.28.0, 8.5.0	2026-06-17T18:18:05.473Z	2026-06-24T10:18:20.293117067Z

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Affected Docker Images

Image Name	SHA
public.ecr.aws/lambda/nodejs:24	public.ecr.aws/lambda/nodejs@sha256:904f7a98db07d37b59bf7edd90ed97bbba1cb574fd86db462205c68cfc55486c

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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.

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Remediation Steps

• Update the affected package undici from version 6.25.0 to 6.27.0, 7.28.0, 8.5.0.

About this issue

• This issue may not contain all the information about the CVE nor the images it affects.
• This issue will not be updated with new information and the list of affected images may have changed since the creation of this issue.
• For more, visit Lambda Watchdog.
• This issue was created automatically by Lambda Watchdog.