CVE-2026-104978

HIGH
Published Oct 5, 2026 Modified Oct 7, 2026 CWE-863

Description

Plane is an open-source project management tool. Prior to 1.4.0, Plane's project invitation list endpoint is accessible to any authenticated user who knows the workspace slug and project ID, while the public project invitation join endpoint accepts an invitation based only on a submitted email address. When a pending invitation targets an email address that has not registered with Plane, an attacker can enumerate the invitation, register an account using the invited email without mailbox verification, and accept the invitation. The attacker-controlled account is then added to the target workspace and project. This issue is fixed in 1.4.0.

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CVSS v3.1 Score

8.2
HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0029
Probability of exploitation
0.19%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-863 Incorrect Authorization

References

Frequently Asked Questions

What is CVE-2026-104978? +
Plane is an open-source project management tool. Prior to 1.4.0, Plane's project invitation list endpoint is accessible to any authenticated user who knows the workspace slug and project ID, while the public project invitation join endpoint accepts an invitation based only on a submitted email address. When a pending invitation targets an email address that has not registered with Plane, an attacker can enumerate the invitation, register an account using the invited email without mailbox verification, and accept the invitation. The attacker-controlled account is then added to the target workspace and project. This issue is fixed in 1.4.0. It has a CVSS v3.1 base score of 8.2 (HIGH).
How severe is CVE-2026-104978? +
CVE-2026-104978 has a CVSS v3.1 score of 8.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-104978? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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