CVE-2026-16728 (MEDIUM): detected in Lambda Docker Images.

## CVE Details

| **CVE ID** | **Severity** | **Affected Package** | **Installed Version** | **Fixed Version** | **Date Published** | **Date of Scan** |
|-----------------|--------------|----------------------|-----------------------|-------------------|--------------------|------------------|
| [CVE-2026-16728](https://avd.aquasec.com/nvd/cve-2026-16728) | `MEDIUM` | `undici` | `6.26.0` | `6.28.0, 7.29.0, 8.9.0` | `2026-07-29T21:17:46.833Z` | `2026-08-04T10:19:08.862184301Z` |

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## Affected Docker Images

| **Image Name** | **SHA** |
|-----------------------------|---------------------------------------|
| `public.ecr.aws/lambda/nodejs:latest` | `public.ecr.aws/lambda/nodejs@sha256:fe69820efd000f4a6a34af1fc61ad476e8266f14fa8ebde7688564efba67a2df` |
| `public.ecr.aws/lambda/nodejs:24` | `public.ecr.aws/lambda/nodejs@sha256:fe69820efd000f4a6a34af1fc61ad476e8266f14fa8ebde7688564efba67a2df` |

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## Description

> undici's retry interceptor can deliver a response whose body length does not match the Content-Length header exposed to the application after a retry or resume of a partial response. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a malicious or faulty upstream can return a partial response with a mismatched framing header, close the socket early, and have the retry interceptor assemble a body of a different length while the original Content-Length stays attached. Applications that use the retry interceptor and forward upstream headers and bodies downstream, such as proxies or gateways, may then emit an invalid HTTP response with a stale Content-Length, leading to downstream response desynchronization, connection hangs, or response corruption. Exploitation requires the retry interceptor enabled, an upstream returning a mismatched partial response, and a downstream forwarder that does not remove or recalculate Content-Length. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.

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### Remediation Steps
- Update the affected package `undici` from version `6.26.0` to `6.28.0, 7.29.0, 8.9.0`.

### 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](https://lambdawatchdog.com).
- This issue was created automatically by Lambda Watchdog.

No repository file or test is named in the issue. Inspect the Docker build inputs and Node.js package manifests for the Lambda images, find where undici 6.26.0 is introduced, and check the image build process; done means the images use a fixed undici version and a follow-up vulnerability scan no longer reports CVE-2026-16728.

Written by the indexing model from the issue text.