CVE-2026-21879 Kanboard vulnerable to Open Redirect via protocol-relative URLs
Attackers can redirect authenticated users to malicious sites via protocol-relative URLs, enabling phishing and credential theft in Kanboard.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-21879?
CVE-2026-21879 is a medium-severity vulnerability in kanboard, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below are vulnerable to an Open Redirect attack that allows malicious actors to redirect authenticated users to attacker-controlled websites. By crafting URLs such as //evil.com, attackers can bypass the filter_var($url, FILTER_VALIDATE_URL) validation check. This vulnerability could be exploited to conduct phishing attacks, steal user credentials, or distribute malware. The issue is fixed in version 1.2.49.
Weakness: CWE-601
Which versions are affected by CVE-2026-21879?
It affects 1 product.
Products include Kanboard Kanboard.
How do I fix CVE-2026-21879?
No fix has been published for CVE-2026-21879 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-21879 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21879 exists.
Other vulnerabilities in kanboard
- CVE-2026-21881 Kanboard is Vulnerable to Reverse Proxy Authentication Bypass
- CVE-2025-55010 Kanboard Authenticated Admin Remote Code Execution via Unsafe Deserialization of Events
- CVE-2024-51747 Arbitrary File Read and Delete in kanboard
- CVE-2024-51748 Remote code execution through language setting in kanboard
- CVE-2017-12850 Business logic in n/a
Sources
Also known as GHSA-mhv9-7m9w-7hcq.