Amazon identifies Oct 17 PHP2Shell exploitation prior to public disclosure

Amazon Threat Intelligence identified a PHP2Shell exploitation attempt dating to Oct. 17, 2026, in MadPot telemetry, four days before public disclosure of CVE-2026-109618 and CVE-2026-109619. The exploit attempt originated from an IP address associated with a commercial anonymization network. While the vulnerability was under embargo, the targeting of a honeypot from an anonymized IP address suggests the activity was conducted by a threat actor, though it remains unclear how the actor acquired exploit information prior to disclosure.

The PHP embargo window was set to be lifted on 2026-10-21 1400 UTC. On the day of the release, Amazon Threat Intelligence identified multiple proof of concept exploits for the vulnerability, with the earliest around 2026-10-21 0200 UTC. Subsequently, from 2026-10-21 0200 UTC to 2026-10-21 0800 UTC, Amazon Threat Intelligence identified additional exploitation attempts of PHP2Shell targeting MadPot from additional anonymized infrastructure. The actual payloads and choices in anonymization infrastructure varied, suggesting these were multiple actors. Technical analysis is ongoing, and it’s unclear if any of these attempts would have succeeded in real-world systems.

The actual release of the embargo window was 2026-10-21 1400 UTC. Once the embargo was lifted and the patch was released, additional proof-of-concept exploits appeared within hours, and we saw them used against our sensors almost immediately. PHP2Shell is now being broadly exploited in the wild.

Two lessons from this event apply well beyond this one vulnerability:

1. An embargo protects defenders only until someone else finds the same bug. Coordinated disclosure is still the right model. But defenders should not assume the public disclosure date is the earliest date of exploitation. With PHP2Shell, compromise may predate the advisory.
2. The time from patch to working exploit is shrinking for structural reasons. In the past, most exploitation we observed came after a public proof of concept was released. A small number of capable actors built exploits, and everyone else waited for them. That dependency is weakening. AI-assisted analysis makes it cheaper to turn a patch diff or advisory into a working exploit. As a result, more actors can act within hours or even minutes once technical details of a vulnerability are disclosed.

For security leaders, this changes several working assumptions:

1. For critical vulnerabilities in internet-facing systems, measure patch and mitigation timelines in hours. A 7-day or 30-day SLA assumes a delay that no longer exists.
2. Start investigations from the earliest known exploitation, not from the disclosure date. For PHP2Shell, investigate from at least starting on October 17^th.
3. Invest in detections that don’t rely on a signature for a specific CVE. The first exploitation will often come before those signatures exist.

AWS deploys multiple layers of protection to help safeguard customers. Our internal threat intelligence system automatically detected and restricted malicious scanning attempts targeting this vulnerability. We analyze over 200 billion events per minute and integrate threat intelligence from our MadPot honeypot network to identify and block known exploitation attempts in real time. Our honeypot system provides us with early detection of exploitation attempts, enabling rapid response and threat analysis.

1. Upgrade immediately to the fixed PHP versions. Upgrading is the only complete remediation for both CVE-2026-109618 and CVE-2026-109619. There are no configuration-only workarounds that fully address both issues.
2. Consider blocking multi-part file uploads in PHP deployments that cannot be patched immediately, but determine how this would affect your application prior to deploying.
3. Look for POST requests with the PHP_SESSION_UPLOAD_PROGRESS string in form uploads.
4. Review web server logs for suspicious activity.
5. Check for unexpected process execution or file modification on web application servers.

IP Address	Observed Date
103.216.220.92	10/17/2026
31.223.184.166	10/21/2026
37.19.200.5	10/21/2026
134.209.159.64	10/21/2026
103.114.163.188	10/21/2026
95.217.98.37	10/21/2026