CVE-2026-104978 makeplane CVE debrief

Who should care

Defenders responsible for managing Plane project instances, particularly those using versions less than 1.4.0, should assess exposure and prioritize upgrading to version 1.4.0 or later.

Why it matters

CVE-2026-104978 is a high-severity vulnerability in the Plane project management tool that allows an attacker to hijack project invitations by exploiting missing authorization and email-only acceptance. Defenders should prioritize verifying exposure and upgrading to version 1.4.0 or later.

• Potential unauthorized account creation
• Possible project membership hijacking
• Required verification of Plane instance exposure
• Necessity to upgrade to version 1.4.0 or later

Technical summary

The Plane project management tool has a vulnerability in its project invitation list endpoint, allowing an attacker to enumerate invitations, register an account using the invited email without mailbox verification, and accept the invitation. The vulnerability has a high severity with a CVSS score of 8.2. Affected deployments should be identified and owners assigned for follow-up. The vulnerability is fixed in version 1.4.0. Defenders should assess exposure and prioritize upgrading to version 1.4.0 or later. The vulnerability allows an attacker to hijack project invitations by exploiting missing authorization and email-only acceptance.

Defensive priority

Defenders should prioritize verifying exposure and upgrading to version 1.4.0 or later.

Recommended defensive actions

• Verify if the Plane project management tool is used in the organization
• Check if the version is less than 1.4.0 and upgrade to 1.4.0 or later if necessary
• Monitor project invitations and join requests for suspicious activity
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and fixed version. The Plane project management tool has a vulnerability in its project invitation list endpoint, allowing an attacker to enumerate invitations, register an account using the invited email without mailbox verification, and accept the invitation. The vulnerability has a high severity with a CVSS score of 8.2. Defenders should verify exposure and prioritize upgrading to version 1.4.0 or later. Evidence is 1.

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.