AWS CDK fixes a symlink flaw in Docker asset bundling in 2.267.0

AWS CDK fixes a symlink flaw in Docker asset bundling in 2.267.0

8 October 2026: Amazon Web Services has fixed CVE-2026-107608 in aws-cdk-lib, the construct library behind the AWS Cloud Development Kit. The flaw lets a Dockerfile used for asset bundling place a symbolic link in the bundling output even though that link was never supplied as input, and it affects every version before 2.267.0. AWS lists the fix as 2.267.0 and rates the bulletin "Important". The linked GitHub advisory, published the same day, scores it 5.5 (Moderate) under CVSS 3.1, as a local attack that needs a user to take part. Neither says whether anyone is exploiting it.

Not yet independently verified. Neither the AWS bulletin nor the GitHub advisory says whether the flaw is being exploited. We will update this when it can be confirmed, and remove this note.

The bulletin is numbered 2026-131-AWS and describes the bug as improper link resolution in how the output of asset bundling is handled. In practice it matters to teams that build assets such as Lambda packages or container contexts inside Docker during cdk synth and cdk deploy, because the bundling container is the place where the stray link can appear.

Fixed version and workaround

The remedy is to upgrade aws-cdk-lib to 2.267.0 or later. AWS also asks anyone who maintains a fork or derivative of the library to apply the same patch to that code.

For teams that cannot upgrade immediately, the bulletin gives one workaround: audit every Docker bundling container and its dependencies, and confirm that no untrusted code runs in the bundling environment. The risk therefore depends on what your build pulls in. A pipeline that bundles only first-party code from pinned base images sits in a different position from one that installs packages at build time from public registries.

Where to look in your own pipelines

Search your CDK projects for bundling options that use Docker, whether through asset bundling settings or custom Dockerfiles, and check which version of aws-cdk-lib each project pins in its lock file. Shared build images and CI runners deserve the same check, because one stale version there can undo upgrades made in individual repositories.

The bulletin links to the CVE record and to GitHub advisory GHSA-h6j4-qpp7-q28p. Our DevOps software category lists 15 products that cover build and deployment automation.

Related on TrustList:

• Docker Engine 29.8.2 fixes DNS trick that disables TLS checks
• Docker Hub fixes critical flaw that passed access tokens to new owners

Sources

• AWS security bulletin 2026-131-AWS: CVE-2026-107608, improper link resolution in aws-cdk-lib, 8 October 2026
• GitHub advisory GHSA-h6j4-qpp7-q28p: aws-cdk-lib symlink in Docker bundling output (CVE-2026-107608), 8 October 2026