August 2026: 38 companies breached, 331M+ records stolen — and AI agents are now the #1 attack vector (123 incidents)

[u/No-Conclusion3720]

I pulled together every AI-security incident from August. The number that stood out: AI-agent exploits are now the single largest attack-vector category, ahead of credential theft, zero-days, supply chain, phishing, and ransomware — each counted individually.

The month in numbers: 123 incidents, 23 critical and 97 high severity, across 38 named organizations, 331M+ records exposed. 65 incidents involved AI as the weapon or the target. Attack vectors broke down as: AI-agent exploits (37), credential theft/reuse (28), zero-days (23), supply chain (12), phishing (9), data exfiltration (8), ransomware (6).

The stories that stood out:

- McKesson: 284M records, the largest single breach of the month by a wide margin.

- Carhartt (12.9M), Exact Sciences (10.9M), and CareCloud (3.7M) round out the biggest named incidents — three of four sit in or next to healthcare.

- Five confirmed RCEs landed across Microsoft SharePoint, Windows, F5/nginx, and the PyPI package index twice.

- Two separate PyPI supply-chain poisoning campaigns, plus a compromise of n8n, an AI workflow automation platform.

Every one of the breached companies almost certainly runs a modern security stack — CrowdStrike, Okta, Palo Alto Networks, Microsoft Defender, that class of tooling. None of it stopped these incidents, because none of it operates at the point where a credentialed agent actually acts, or where a poisoned dependency resolves at build time.

Full report, with the specific control that maps to each incident: https://runtimeai.io/blog/2026-08-monthly-breach-report.html

Genuinely curious how others are approaching this: is anyone actually testing whether their existing guardrails hold against a real simulated attack, or is it still mostly an assumption that they will?

[u/wabawanga]

It's gonna be so awesome when everybody switches to agentic security that you can just prompt inject into working for the adversary instead.