We estimate the complete rollout for live environments on supported PHP versions (8.2 -> 8.5) within the next 20 minutes.
We are also prioritizing pre-production environments for paying customers, and have preemptively patched development or mutli-dev environments that were toggled into a mutable code state (“SFTP mode”).
We will provide an update on LTS versions of PHP (8.1.x through 5.6.x) once our upstream vendor has backported the patches and made updates available. That work has been in progress since 14:00 UTC.
Our network-level mitigations remain effective, and are blocking a low but slowly increasing level of activity which is probing the vulnerable surface area. At this time we do not see evidence of widespread exploitation attempts, or any successful exploits.
We will continue to deliver patched versions of PHP as quickly as possible, and maintain network level mitigation and continuous monitoring to provide our customers and the wider PHP community insights into how this situation plays out
Posted Oct 21, 2026 - 12:30 PDT
Identified
Patching continues to roll out across the infrastructure in stages, with protective mitigations remaining active. We have not observed any volumetric exploit attempts, and no customer action is required.
We expect to provide an estimated completion time for the patching rollout within the next hour.
Posted Oct 21, 2026 - 11:22 PDT
Update
Patches continue rolling out across the infrastructure in stages, and protective mitigations remain active. We have not observed any volumetric exploit attempts, and no customer action is required.
Posted Oct 21, 2026 - 10:17 PDT
Update
Patching work is still in progress. Environments are being updated in stages, and protective mitigations remain active across the platform while the remaining updates complete.
We are not yet seeing evidence of any volumetric exploit attempts. No customer action is needed. We will provide further updates as the rollout progresses.
Posted Oct 21, 2026 - 09:07 PDT
Update
Updated PHP versions addressing CVE-2026-109618 and CVE-2026-109619 are now available, and we are beginning the process of rolling them out across our infrastructure.
No action is required from customers.
We will continue to update this post as the rollout progresses.
Posted Oct 21, 2026 - 07:36 PDT
Investigating
Pantheon is actively mitigating against the PHP security vulnerabilities announced at 14:00 UTC today. PHP environments are being patched to the following versions:
8.5.12 8.4.27 8.3.36 8.2.35
Additionally, we are patching the following heirloom PHP branches via our LTS vendor:
8.1.x 8.0.x 7.4.x 7.3.x 7.2.x 7.1.x 7.0.x 5.6.x
Finally, in preparation for this event, we pre-emptively deployed configuration changes to the runtime environment to mitigate potential attack vectors, and have implemented network-level mitigations to deflect attempted exploit payloads across the platform.
No action is required from customers, as all available versions of PHP on Pantheon receive security updates through our LTS vendor. However, we continue to recommend that customers running on older versions of PHP that have reached End of Sale update to a version fully supported by the PHP community in order to minimize their overall risk.