CVE-2026-76647 Leantime CVE debrief

Who should care

Defenders responsible for Leantime installations, security teams monitoring for suspicious activity, and administrators of affected systems should be aware of this vulnerability and take necessary actions to mitigate it.

Why it matters

CVE-2026-76647 is a high-severity vulnerability in the Leantime JSON-RPC API that allows authenticated users to act outside their intended permissions, potentially leading to account takeover and unauthorized access. Defenders should prioritize verifying and patching affected installations, restricting access, and monitoring for suspicious activity.

• Account takeover through exploitation of the editOwn method
• Potential for lateral movement and unauthorized access to sensitive resources
• Need for verification of affected versions and deployments
• Priority for patching and restricting access to the JSON-RPC API

Technical summary

The Leantime JSON-RPC API through version 3.9.0 contains a missing authorization vulnerability in the JSON-RPC dispatcher. This allows an authenticated user to call methods or act on resources outside their intended permissions. For example, the editOwn method can be used to modify another user's account and set a new password, leading to account takeover. Defenders should prioritize verifying and patching affected Leantime installations, restricting access to the JSON-RPC API, and monitoring for suspicious activity to mitigate potential impacts, including account takeover and unauthorized access to sensitive resources.

Defensive priority

Defenders should prioritize verifying and patching affected Leantime installations, restricting access to the JSON-RPC API, and monitoring for suspicious activity.

Recommended defensive actions

• Verify and apply patches for Leantime JSON-RPC API version 3.9.0 or earlier
• Restrict access to the JSON-RPC API to only necessary users and services
• Monitor for suspicious activity and implement additional logging and monitoring for the JSON-RPC API
• 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 NVD entry provide details on the vulnerability, including its CVSS score of 8.8 and the affected component. However, the exact scope of affected versions and deployments is not specified.

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.