How severe is CVE-2026-21879?

CVE-2026-21879 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-21879 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21879?

CVE-2026-21879 affects Kanboard. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21879?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-21879 have an EU (EUVD) identifier?

Yes. CVE-2026-21879 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1665.

When was CVE-2026-21879 published?

CVE-2026-21879 was published on 2026-01-08 and last updated on 2026-06-17.

CVE-2026-21879

CVE-2026-21879 is a medium-severity vulnerability in Kanboard with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-1665
Weakness: CWE-601
Affected product: Kanboard
Published: 2026-01-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-21879?: 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.
How severe is CVE-2026-21879?: CVE-2026-21879 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-21879 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21879?: CVE-2026-21879 affects Kanboard. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21879?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21879 have an EU (EUVD) identifier?: Yes. CVE-2026-21879 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1665.
When was CVE-2026-21879 published?: CVE-2026-21879 was published on 2026-01-08 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kanboard:kanboard:*:*:*:*:*:*:*:*

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Other CWE-601 (Open Redirect) vulnerabilities

CVE-2018-3774 — Critical (CVSS 10.0): Incorrect parsing in url-parse <1.4.3 returns wrong hostname which leads to multiple vulnerabilities such as SSRF, Open…
CVE-2019-25282 — Critical (CVSS 9.8): V-SOL GPON/EPON OLT Platform v2.03 contains an open redirect vulnerability in the script that allows attackers to…
CVE-2020-36912 — Critical (CVSS 9.8): Plexus anblick Digital Signage Management 3.1.13 contains an open redirect vulnerability in the 'PantallaLogin' script…
CVE-2025-43526 — Critical (CVSS 9.8): This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac…
CVE-2025-55031 — Critical (CVSS 9.8): Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An…
CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.

Browse all CWE-601 (Open Redirect) vulnerabilities →