Vulnerability · Published Aug 4, 2026 · Assigned by AMZN

CVE-2026-18830Insufficient input validation in Amazon Bedrock AgentCore harness InvokeHarness API

High 8.1

In plain English

A high-severity security flaw in Amazon Bedrock AgentCore harness from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.5%top 56.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling1Public PoC

Official description

Insufficient input validation in Amazon Bedrock AgentCore harness might allow an authenticated remote user to execute configured tools bypassing model invocation and security controls via crafted content blocks in conversation messages. AWS has addressed this issue. No customer action is required.

Affected products (as reported)

Vendor	Product	Versions
AWS	Amazon Bedrock AgentCore harness	N/A

Weakness: CWE-1287 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

https://aws.amazon.com/security/security-bulletins/2026-073-aws/ vendor-advisory