High · CVSS 8.7CVE-2026-104979

Plane: Cross-tenant stored XSS in intake enables account takeoverCVE-2026-104979

Answer in brief

CVE-2026-104979 records a High severity (CVSS 8.7) vulnerability in Plane: Cross-tenant stored XSS in intake enables account takeover. The current sources do not mark it as known exploited. The current feed maps makeplane/plane (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 5, 2026Updated Oct 5, 2026Source checked Oct 5, 2026First seen by HOL Oct 5, 2026Material review Oct 5, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps makeplane/plane (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
makeplane/planegeneric	<1.4.0	1.4.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for makeplane/plane.
Review the reported fix. Update makeplane/plane to 1.4.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 5, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.