[Feature Request] Add nodejs26.x runtime support to SAM specification

[rgoltz]

Node.js 26 was released on 2026-05-05 as the upcoming LTS version. The SAM transform / specification needs to recognize nodejs26.x as a valid Lambda runtime value so that SAM templates using the new runtime are accepted and correctly transformed into CloudFormation templates.

Requested changes

• Add nodejs26.x to the list of supported Lambda runtimes in the SAM specification schema and transform validator
• Update integration-test templates (e.g. in integration/resources/templates/) that reference Node.js runtimes to
  include or cover nodejs26.x
• Update any documentation examples that reference the latest Node.js runtime

Relationship to other SAM components
This is part of a chain of SAM-related issues for nodejs26.x support:

• Feature request: Add Node.js 26 build image (nodejs26.x) aws-sam-build-images#193 (prerequisite)
• Feature request: Add nodejs26.x runtime support aws-sam-cli#8953

[roger-zhangg]

Triage note on why this has not moved, since it has had no replies: the whole nodejs26.x chain is blocked on an upstream prerequisite that has not been actioned.

aws/aws-lambda-base-images#488 ("Add Node.js 26 base image") is still open and untouched since 2026-05-06. Nothing downstream can land before it:

1. [Feature Request] Add Node.js 26 base image (public.ecr.aws/lambda/nodejs:26) aws-lambda-base-images#488 — Lambda base image (blocker, unactioned)
2. Feature request: Add Node.js 26 build image (nodejs26.x) aws-sam-build-images#193 — SAM build image, needs (1)
3. [Feature Request] Add nodejs26.x runtime support to SAM specification #3922 — SAM spec/transform accepts nodejs26.x, needs (2)
4. Feature request: Add nodejs26.x runtime support aws-sam-cli#8953 — SAM CLI runtime support, needs (2) and (3)

For reference, samtranslator currently tops out at nodejs24.x. Each of steps 2-4 is mechanical once unblocked; none of them is the thing to work on first.

Leaving this open and tracking #488 as the real dependency, so these stop looking simply ignored.