# CVE-2026-104965: Plane: Cross-Tenant Issue Relation Creation via IDOR

> Authenticated users can link their issues to other workspaces via IDOR, leaking metadata and modifying relations in Plane project management.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-8cvv-8jh5-g6mj

## What is CVE-2026-104965?

CVE-2026-104965 is a medium-severity missing authorization vulnerability in makeplane plane, published on 5 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Plane is an open-source project management tool. Prior to 1.4.0, the issue-relation endpoint accepts issue UUIDs in the request body without validating that they belong to the caller's workspace. An authenticated user can create relations linking their own issues to issues in any other workspace on the instance, leaking issue metadata through activity events. This issue is fixed in 1.4.0.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-104965?


## How do I fix CVE-2026-104965?

No fix has been published for CVE-2026-104965 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104965 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104965 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104965 and fix it if it is affected.

What it is: CVE-2026-104965 is a medium-severity missing authorization vulnerability in makeplane plane, published on 5 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104965 exists.

Affected product: makeplane plane. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-104965/ (Markdown: https://insights.sbomify.com/CVE-2026-104965/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104965
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104965
- OSV: https://osv.dev/vulnerability/CVE-2026-104965

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104965/
Summaries are generated and may contain mistakes; the official description above is the record.