CVE-2026-9255 Tool Execution Without Authorization via Piped Stdin in Kiro CLI
A local attacker can execute arbitrary tools and shell commands without user approval by piping crafted content to Kiro CLI stdin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-9255?
CVE-2026-9255 is a high-severity missing authorization vulnerability in AWS Kiro CLI, published on 22 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Missing input source validation in the tool authorization prompt in Kiro CLI before 1.28.0 allows a local attacker to execute arbitrary tools, including shell commands, without user approval by crafting content that is piped to kiro-cli via stdin.
We recommend you to upgrade to kiro-cli version 1.28.0 or later.
Weakness: CWE-862
Which versions are affected by CVE-2026-9255?
It affects 1 product.
Products include Amazon Kiro Cli.
How do I fix CVE-2026-9255?
No fix has been published for CVE-2026-9255 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-2026-9255 being exploited?
There is no known exploitation of CVE-2026-9255 in the wild and no public exploit code.
Other vulnerabilities in AWS Kiro CLI
Sources
Also known as GHSA-cv6r-hx5v-c4m6.