CVE-2026-39843
CWE-918Published: April 9, 2026· Updated: Apr 13, 2026
Official Description
Plane is an an open-source project management tool. From 0.28.0 to before 1.3.0, the remediation of GHSA-jcc6-f9v6-f7jw is incomplete which could lead to the same full read Server-Side Request Forgery when a normal html page contains a link tag with an href that redirects to a private IP address is supplied to Add link by an authenticated attacker with low privileges. Redirects for the main page URL are validated, but not the favicon fetch path. fetch_and_encode_favicon() still uses requests.get(favicon_url, ...) with the default redirect-following. This vulnerability is fixed in 1.3.0.
Technical Analysis
CVE-2026-39843 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.7.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (1)
Quick Facts
Related CVEs (CWE-918)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-39843 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts