CVE-2026-105811 Authorization bypass through a user-controlled key in the Amazon Q Business Lambda hook sample in QnABot on AWS

What is CVE-2026-105811?

CVE-2026-105811 is a high-severity missing authorization vulnerability in qnabot-on-aws, published on 6 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Authorization bypass through a user-controlled key in the optional Amazon Q Business Lambda hook sample ( q-business-lambda-hook https://github.com/aws-solutions-library-samples/qnabot-on-aws/blob/main/source/docs/lambda_hooks/README.md ), available with QnABot on AWS versions 7.0.0 through 7.4.5, might allow an authenticated remote user to read arbitrary Amazon S3 objects in the deploying AWS account. This sample solution provides an example Lambda hook and requires separate, manual deployment and additional setup. It is not deployed automatically with QnABot. Customers who have not deployed this optional sample hook are not affected and do not need to take action.

To remediate this issue, affected customers should update the QnABot on AWS stack to version 7.4.6 or later and then redeploy the Amazon Q Business Lambda hook sample stack. Updating the QnABot on AWS stack alone does not deliver the fix.

Weakness: CWE-639

Which versions are affected by CVE-2026-105811?

How do I fix CVE-2026-105811?

No fix has been published for CVE-2026-105811 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-105811 being exploited?

There is no known exploitation of CVE-2026-105811 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-r223-2773-wq4w.