GHSA-6v7p-g79w-8964 (HIGH): detected in Lambda Docker Images.

## CVE Details

| **CVE ID** | **Severity** | **Affected Package** | **Installed Version** | **Fixed Version** | **Date Published** | **Date of Scan** |
|-----------------|--------------|----------------------|-----------------------|-------------------|--------------------|------------------|
| [GHSA-6v7p-g79w-8964](https://github.com/advisories/GHSA-6v7p-g79w-8964) | `HIGH` | `msgpack` | `1.1.2` | `1.2.1` | `2026-06-19T21:42:55Z` | `2026-08-13T10:18:42.129576392Z` |

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## Affected Docker Images

| **Image Name** | **SHA** |
|-----------------------------|---------------------------------------|
| `public.ecr.aws/lambda/python:3.13` | `public.ecr.aws/lambda/python@sha256:4763641547a2bd881065e0b196d2887369876e524561b12519e2662fde3361e5` |

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## Description

> ### Impact

If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV.

If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack.

### Patches

v1.2.1

### Workarounds

Users should create a new Unpacker instead of reusing the same Unpacker after an error occurs.

Applying the above patch can prevent SEGV, but reusing the Streaming Unpacker after it has encountered an error will not yield correct data. If an error occurs during Streaming Unpacking, the Stream and Streaming Unpacker should be discarded.

Therefore, this is not just a workaround but the correct solution. The above patch only prevents crashes from incorrect usage.

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### Remediation Steps
- Update the affected package `msgpack` from version `1.1.2` to `1.2.1`.

### 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.

Start by reading GHSA-6v7p-g79w-8964 and inspecting the build configuration for public.ecr.aws/lambda/python:3.13. Update msgpack from 1.1.2 to 1.2.1, then verify that the affected Lambda image no longer contains the vulnerable version.

Written by the indexing model from the issue text.