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Vulnerabilities

Security fix · CVE-2026-21881

Kanboard is project management software focused on Kanban methodology.

Published Jan 8, 2026 · catalog updated Jan 8, 2026 · Kanboard is project management

Last checked Nov 3, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-21881. EPSS is 0.49%. Act only if a listed version of Kanboard is project management is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Kanboard is project management).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.49%
Remediation
Version ranges on file
Affected products
vendor kanboard kanboard < 1.2.49

Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled. The application blindly trusts HTTP headers for user authentication without verifying the request originated from a trusted reverse proxy. An attacker can impersonate any user, including administrators, by simply sending a spoofed HTTP header. This issue is fixed in version 1.2.49.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor kanboard kanboard < 1.2.49< 1.2.49

How to fix CVE-2026-21881

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-21881. EPSS is 0.49%. Act only if a listed version of Kanboard is project management is installed.

Which versions are affected?

Compare what you have installed with kanboard kanboard < 1.2.49 < 1.2.49. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.49%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 8, 2026 · EUVD

    Detected

    Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled. The application blindly trusts HTTP headers for user authentication without verifying the request originated from a trusted reverse proxy. An attacker can impersonate any user, including administrators, by simply send

  2. Jan 8, 2026 · EUVD

    Updated

    Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled. The application blindly trusts HTTP headers for user authentication without verifying the request originated from a trusted reverse proxy. An attacker can impersonate any user, including administrators, by simply send

Sources

  • CVE.orgVulnerability recordCVE-2026-21881

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-21881

    30-day exploitation probability 0.49%

    first.org
  • EUVDVulnerability recordEUVD-2026-1668

    Kanboard is project management software focused on Kanban methodology. Versions 1.2.48 and below is vulnerable to a critical authentication bypass when REVERSE_PROXY_AUTH is enabled. The application blindly trusts HTTP headers for user authentication without verifying the request

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 3, 2026
  • CVE.orgOct 31, 2026
  • EUVDOct 30, 2026