CodeBreach: How a 2-Character Typo Exposed AWS

From Regex to Regret: Inside the Vulnerability That Exposed AWS

Dateline: January 16, 2026

In a stunning revelation that highlights the fragility of modern software supply chains, security researchers have disclosed a critical vulnerability in AWS CodeBuild that left key Amazon Web Services (AWS) repositories wide open to hijackers.

Dubbed "CodeBreach" by the team at Wiz Research who discovered it, the flaw could have allowed unauthenticated attackers to seize control of the AWS JavaScript SDK—a foundational library that powers the AWS Console itself.

The incident highlights a critical challenge for security teams: configuration complexity has outpaced human capacity to review it manually. When a missing regex anchor can expose millions of users, security leaders need automated, context-aware monitoring that operates 24/7—not just periodic peer reviews.

The Flaw: Missing Anchors

The vulnerability stemmed from a subtle misconfiguration in how AWS CodeBuild handled webhook filters. To prevent unauthorized code changes, AWS configured its build pipelines to only accept commands from trusted GitHub user IDs.

However, the Regular Expression (regex) used to validate these IDs was "unanchored."

In regex terms, anchors are characters that denote the start (^) and end ($) of a string. Without them, the system didn't look for an exact match—it only checked if the trusted ID existed somewhere in the requester's ID.

• Trusted ID: 12345
• Attacker ID: 99912345999

Because the attacker's ID contained the trusted string, the unanchored filter let it pass, effectively tricking the system into treating an outsider as a privileged maintainer.

The "Needle in a Haystack" Problem

This specific error highlights a growing crisis in software development. The AWS engineers who wrote this code are world-class experts. Yet, a missing caret (^) or dollar sign ($) is incredibly difficult for the human eye to spot during a peer review, especially when buried in thousands of lines of configuration files.

This is where Secure.com's Digital Security Teammates provide value.

Unlike traditional static analysis tools that flood developers with false positives, Secure.com's Digital Security Teammates are AI-native agents that provide context-aware security analysis across your entire infrastructure (from code to cloud) understanding not just syntax but business context, asset criticality, and attack paths.

In the case of CodeBreach:

• A Human Reviewer sees a regex pattern and assumes it works because it looks standard.
• Secure.com's Digital Security Teammates would flag this misconfiguration during continuous infrastructure scanning, correlating it with the asset's criticality (AWS SDK repository), the blast radius (millions of AWS Console users), and existing vulnerabilities—then routing a prioritized remediation ticket to the responsible owner with full context and suggested fixes.

From Bypass to Total Takeover

Without that digital safety net, the researchers were able to bypass the filter and trigger a build process within the aws-sdk-js-v3 repository.

Once inside, they extracted a GitHub Personal Access Token (PAT) belonging to an automation bot, granting them administrative control. In a real-world scenario, an attacker could have injected malicious backdoors into the SDK, compromised the npm registry, and effectively hijacked the AWS Console for millions of users.

The Fix and The Future

Wiz privately disclosed the vulnerability to AWS in August 2025. AWS patched the regex flaw within 48 hours and revoked the exposed tokens. AWS stated there was no evidence of malicious exploitation.

However, the lesson remains. Complexity in CI/CD pipelines has outpaced human ability to secure it manually.

Takeaways for the Modern Engineering Team

• Anchor Your Regex: Always use ^ (start) and $ (end) anchors when validating specific strings like user IDs, API keys, or access tokens. Unanchored patterns create substring matching vulnerabilities that attackers exploit through ID spoofing, parameter injection, and privilege escalation.
• Sanitize Inputs: Never trust parameters (like ACTOR_ID) blindly.

Adopt Secure.com's Digital Security Teammates

Modern security requires continuous, automated monitoring that goes beyond manual peer review.

Secure.com's platform provides real-time infrastructure scanning, misconfiguration detection, and risk-based prioritization—correlating configuration issues with asset criticality, attack paths, and compliance requirements to surface the high-impact risks that manual reviews miss.

But it serves as a powerful validation that in the era of AI-scale threats, developers need AI-scale teammates to keep the doors locked.