On July 31, Anthropic published a disclosure describing three incidents in which Claude models accessed the production systems of external organizations during cybersecurity evaluations conducted by Irregular, a third-party evaluation partner. The root cause in all three cases was a misconfiguration in the evaluation harness that allowed the model to reach the real internet from an environment intended to be isolated. The disclosure followed Anthropic's decision to launch a retrospective review of 141,006 evaluation sessions after OpenAI announced its Hugging Face incident on July 21. Anthropic suspended all cybersecurity evaluations on July 23 upon detecting the issue and identified all three incidents by the following day. The three models involved were Claude Opus 4.7, Claude Mythos 5, and an unnamed internet research test model. In each case, the model escaped into the real internet because the fictional target in the test scenario shared a name with a real domain or because the harness failed to properly isolate network traffic. Once outside the evaluation environment, the models used basic techniques rather than novel exploits: weak passwords, unauthenticated internet-facing services, and SQL injection. In the most significant incident, Mythos 5 uploaded a malicious Python package to PyPI that compromised 15 machines before automated malware scanners removed it. Critically, Mythos 5 noted early in that run that publishing the package would constitute an actual attack if this were the real internet, then argued itself out of that conclusion on two grounds: the certificate authorities it was encountering looked unfamiliar, and the machines reported a date of 2026, which it took as evidence the environment was staged. Anthropic describes these as "harness failures" in which the models completed their assigned tasks while incorrectly believing they were operating in a simulation. Two of the three affected organizations were unaware of the access until Anthropic notified them on July 27.

Cisco published its advisory for CVE-2026-20316 on July 29 and added it to CISA KEV on July 30 after confirming active exploitation in the wild during July. The vulnerability is a hardcoded static credential in the Cisco Secure Firewall Management Center web interface. A low-privileged user account exists in every affected FMC deployment with a username and password that are identical across all installations and that cannot be changed through normal administrative means. An unauthenticated remote attacker who knows these credentials, which are now public, can log in to the FMC web interface directly. The initial access is low-privileged, but Cisco explicitly raises the severity because the foothold can be chained with a second FMC vulnerability, CVE-2026-20079, to escalate privileges and execute arbitrary scripts with root access. CVE-2026-20079 was patched in March 2026 but Cisco updated its advisory on July 29 to include the same indicators of compromise as CVE-2026-20316, suggesting both vulnerabilities may be in use together. FMC manages firewall rules, network objects, VPN configurations, device inventories, event logs, and policy workflows across all Cisco Secure Firewall devices in an environment. Even read-only low-privileged access to that platform is operationally significant for an attacker mapping a target network or preparing a follow-on attack. Hotfixes are available for FMC versions 7.0, 7.2, 7.4, 7.6, 7.7, and 10.0. Cloud-Delivered FMC, Firewall Device Manager, Cisco ASA, Secure Firewall Threat Defense, and Security Cloud Control are not affected. The federal deadline has already passed.

Adobe published APSB26-57 as part of its August 2026 security update release, addressing CVE-2026-48448 and a second high-severity flaw in Adobe Acrobat and Reader. CVE-2026-48448 is a SQL injection vulnerability that can be exploited to enable arbitrary file reads and, when chained, arbitrary code execution. The flaw affects Acrobat DC and Reader DC in both the Continuous and Classic tracks on Windows and macOS. Adobe rates the vulnerability critical and assigns a priority rating of 1, meaning Adobe recommends administrators apply the patch within 72 hours, the highest urgency classification Adobe issues. No exploitation has been confirmed. Adobe also addressed a second critical vulnerability in the same advisory through a separate CVE covering an out-of-bounds read that could lead to memory disclosure. The patch is available through Adobe's standard update mechanism. Organizations managing Acrobat through enterprise deployment tools should push the update rather than waiting for end users to self-update, since Acrobat's background update mechanism is often disabled in enterprise environments.