AWS SDK for JavaScript v3 adopted defense in depth enhancement for region parameter value

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

CVSSv3.1 Rating: 3.7 (LOW) Summary This notification is related to the use of specific values for the region input field when calling AWS services. An actor with access to the environment in which the SDK is used could set the region input field to an invalid value. A defense-in-depth enhancement has been implemented in the AWS SDK for JavaScript v3 (versions 3.723.0 and later). This enhancement validates that a region used to construct an endpoint URL is a valid host label. The change was released on November 15, 2025. This advisory is informational to help customers understand their responsibilities regarding configuration security. Impact Customer applications could be configured to improperly route AWS API calls to non-existent or non-AWS hosts. While the SDK was functioning as designed, additional safeguards have been added to support secure customer implementations. Impacted versions: @smithy/config-resolver <4.4.0 Patches On November 15, 2025, an enhancement was made to the…

Published by the source

8 Jan 2026, 21:52 UTC

Last modified by the source

10 Sep 2026, 03:49 UTC

Source last checked

26 Oct 2026, 12:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6475-r3vj-m8vf

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6475-r3vj-m8vf

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# Patch Next advisory brief: GHSA-6475-r3vj-m8vf

Advisory: AWS SDK for JavaScript v3 adopted defense in depth enhancement for region parameter value
IDs: GHSA-6475-r3vj-m8vf
Record: https://patchnext.com/advisories/ghsa-6475-r3vj-m8vf (revision 2, source checked 26 Oct 2026, 12:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @smithy/config-resolver 4.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @smithy/config-resolver: affected < 4.4.0; fixed in 4.4.0

## Suggested inspection (read-only)
- `npm ls @smithy/config-resolver --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @smithy/config-resolver.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6475-r3vj-m8vf (OSV record GHSA-6475-r3vj-m8vf lists affected ranges: npm @smithy/config-resolver >=0 <4.4.0 (fixed))
- Verified: https://github.com/advisories/GHSA-6475-r3vj-m8vf (GitHub-reviewed advisory GHSA-6475-r3vj-m8vf lists affected ranges: npm @smithy/config-resolver >=0 <4.4.0)

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