CVE-2026-105636 makeplane CVE debrief

Who should care

Defenders responsible for Plane installations, especially those with access to cloud metadata, should assess exposure and prioritize updating to version 1.4.0 or applying compensating controls.

Why it matters

CVE-2026-105636 is a critical SSRF vulnerability in Plane's webhook delivery, allowing for potential exposure of internal resources. Defenders should prioritize verifying exposure and updating to version 1.4.0 or applying compensating controls.

• Potential exposure of internal resources, including cloud metadata
• Possible unauthorized access to sensitive information
• Need for verification of Plane installations' exposure
• Priority for updating to version 1.4.0 or applying compensating controls

Technical summary

The webhook delivery task in Plane's apps/api/plane/bgtasks/webhook_task.py calls requests.post() without allow_redirects=False, allowing for SSRF via HTTP redirect. An attacker can register a webhook pointing to a controlled public endpoint that returns a 302 redirect to an internal address, fetching internal resources such as cloud metadata. This issue is fixed in version 1.4.0, where validation of redirect targets is added. Defenders should prioritize verifying exposure of Plane installations to internal resources, especially those with access to cloud metadata.

Defensive priority

Defenders should prioritize verifying exposure of Plane installations to internal resources, especially those with access to cloud metadata. Immediate action is required to update to version 1.4.0 or apply compensating controls to restrict webhook delivery.

Recommended defensive actions

• Update Plane to version 1.4.0 or later
• Restrict webhook delivery to trusted endpoints
• Monitor webhook logs for suspicious activity
• Verify exposure of Plane installations to internal resources
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and the fix in version 1.4.0. However, specific details about exploitation or victim organizations are not provided. Defenders should verify exposure of Plane installations to internal resources, especially those with access to cloud metadata, and prioritize updating to version 1.4.0 or applying compensating controls. Evidence is limited to public sources and CVE metadata.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.