CVE-2026-57862 Kanboard 1.2.52 and prior SSRF Filter Bypass via Hexadecimal IP Notation
Authenticated users can bypass SSRF filters using hexadecimal IP notation to access internal network resources and cloud metadata services.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-57862?
CVE-2026-57862 is a high-severity server-side request forgery vulnerability in Kanboard, published on 30 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Kanboard 1.2.52 and prior contains a server-side request forgery vulnerability that allows authenticated users to bypass SSRF protections by supplying hexadecimal IP address notation in user-controlled URLs. Attackers can submit hexadecimal-encoded internal IP addresses through the web link creation feature, causing cURL to resolve and connect to internal network resources such as cloud instance metadata services, localhost services, and RFC1918 addresses while the isPrivateURL() filter in app/Core/Http/Client.php incorrectly treats the input as safe due to FILTER_VALIDATE_IP rejecting non-dotted-decimal notation.
Weakness: CWE-918
Which versions are affected by CVE-2026-57862?
How do I fix CVE-2026-57862?
No fix has been published for CVE-2026-57862 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-57862 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57862 exists.
Sources
Also known as GHSA-rj28-q96f-28vw.