CVE-2026-104979 Plane: Cross-tenant stored XSS in intake enables account takeover
Authenticated users can inject malicious HTML into intake issues, leading to stored XSS and API token exfiltration when viewed by others.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-104979?
CVE-2026-104979 is a high-severity cross-site scripting vulnerability in makeplane plane, published on 5 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2026-104979?
How do I fix CVE-2026-104979?
No fix has been published for CVE-2026-104979 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-104979 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104979 exists.
Sources
Also known as GHSA-hh2r-3hwp-mvq3.