kanboard up to 1.2.48 filter_var url redirect

Summaryinfo

A vulnerability, which was classified as problematic, has been found in kanboard up to 1.2.48. The affected element is the function filter_var. Performing a manipulation of the argument url results in redirect. This vulnerability is known as CVE-2026-21879. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in kanboard up to 1.2.48. This affects the function filter_var. The manipulation of the argument url with an unknown input leads to a redirect vulnerability. CWE is classifying the issue as CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-21879 since 01/05/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1204.001 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 282470 (Linux Distros Unpatched Vulnerability : CVE-2026-21879), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.2.49 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 93bcae03301a6d34185a8dba977417e6b3de519f is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (282470). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Forum Software

Name

• kanboard

Version

• 1.2.0
• 1.2.1
• 1.2.2
• 1.2.3
• 1.2.4
• 1.2.5
• 1.2.6
• 1.2.7
• 1.2.8
• 1.2.9
• 1.2.10
• 1.2.11
• 1.2.12
• 1.2.13
• 1.2.14
• 1.2.15
• 1.2.16
• 1.2.17
• 1.2.18
• 1.2.19
• 1.2.20
• 1.2.21
• 1.2.22
• 1.2.23
• 1.2.24
• 1.2.25
• 1.2.26
• 1.2.27
• 1.2.28
• 1.2.29
• 1.2.30
• 1.2.31
• 1.2.32
• 1.2.33
• 1.2.34
• 1.2.35
• 1.2.36
• 1.2.37
• 1.2.38
• 1.2.39
• 1.2.40
• 1.2.41
• 1.2.42
• 1.2.43
• 1.2.44
• 1.2.45
• 1.2.46
• 1.2.47
• 1.2.48

License

• open-source

Website

• Product: https://github.com/kanboard/kanboard/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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