# CVE-2026-104973: Plane DNS rebinding bypass in webhook delivery SSRF protection

Source: https://junglewise.ai/threats/cve-2026-104973-plane-is-an-open-source-project-management-tool-prior-to-1-4-0  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-104973 · Severity: high · CVSS 7.6 · Published 2026-10-05

Plane is an open-source project management tool that allows teams to manage and track work items. The webhook delivery feature, which sends notifications to external URLs when events occur, contained a server-side request forgery (SSRF) vulnerability. An attacker could use DNS rebinding techniques to bypass the SSRF protections and access internal systems or data by manipulating DNS responses during webhook delivery.

Technologies: [Makeplane Plane](https://junglewise.ai/threats/technologies/plane). Vendors: [Makeplane](https://junglewise.ai/threats/vendors/makeplane).

## Quick answers

**Is CVE-2026-104973 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104973 being exploited in the wild.

**How severe is CVE-2026-104973?** High severity, with a CVSS score of 7.6, published 5 October 2026.

**Which products and versions are affected?** Makeplane Plane before 1.4.0.

**Is there a fix for CVE-2026-104973?** Yes: fixed in 1.4.0. Until then: Upgrade to version 1.4.0 or later, which implements a pinned-IP HTTP client that resolves and validates DNS once before connecting, eliminating the DNS rebinding window. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-104973 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-104973?** Check whether you run Makeplane Plane at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.4.0

Upgrade to version 1.4.0 or later, which implements a pinned-IP HTTP client that resolves and validates DNS once before connecting, eliminating the DNS rebinding window.

## Technical details

The vulnerability is a DNS rebinding time-of-check-time-of-use (TOCTOU) flaw in webhook delivery. IP validation occurred when the webhook was created in the serializer, but the delivery task in webhook_task.py performed a separate DNS resolution at send time without validating the resolved IP, allowing an attacker to return different IPs for the same hostname between validation and delivery. This is fixed by using a pinned-IP HTTP client that resolves DNS once, validates the result, and connects to the validated IP literal.

## Affected products

- makeplane Plane before 1.4.0

## Timeline

- 2026-10-05: disclosed
- 2026-05-31: patched: Fix merged in PR #9163

## References

- [https://github.com/makeplane/plane/commit/04622ce1188c4680951f0001e35efb342fe51615](https://github.com/makeplane/plane/commit/04622ce1188c4680951f0001e35efb342fe51615)
- [https://github.com/makeplane/plane/pull/9163](https://github.com/makeplane/plane/pull/9163)

## Related threats

- [makeplane plane rate limit bypass via X-Forwarded-For header](https://junglewise.ai/threats/cve-2026-111869-a-vulnerability-was-identified-in-makeplane-plane-up-to-1-4-2)
- [Plane account takeover via unverified OAuth email](https://junglewise.ai/threats/cve-2026-105640-plane-is-an-open-source-project-management-tool-prior-to-1-4-0)
- [Plane project management asset IDOR in bulk-asset endpoint](https://junglewise.ai/threats/cve-2026-105637-plane-is-an-open-source-project-management-tool-prior-to-1-4-0)
- [Plane privilege escalation in project member role updates](https://junglewise.ai/threats/cve-2026-105634-plane-is-an-open-source-project-management-tool-prior-to-1-3-0)
- [Plane project management tool asset access control bypass](https://junglewise.ai/threats/cve-2026-105631-plane-is-an-open-source-project-management-tool-prior-to-1-4-0)