Input Validation Flaw in Amazon Bedrock AgentCore by AWS
CVE-2026-18830

8.6HIGH

Key Information:

Vendor

Aws

Status
Amazon Bedrock Agentcore Harness
Vendor
CVE Published:
4 August 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-18830?

An input validation flaw in Amazon Bedrock AgentCore may permit an authenticated remote user to execute predefined tools, circumventing standard model invocation and security protocols through specially crafted content blocks embedded in conversation messages. AWS has resolved the issue, and no further action is required from customers.

Affected Version(s)

Amazon Bedrock AgentCore harness

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

aegisagent
Created by huzjie

References

https://aws.amazon.com/security/security-bulletins/2026-0...
vendor-advisory

CVSS V4

Score:
8.6
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.