CVE-2026-25561
Published: 07 February 2026
Summary
CVE-2026-25561 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Wekan Project Wekan. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 2.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-25561, published on 2026-02-07, affects WeKan versions prior to 8.19 and stems from an authorization weakness (CWE-863) in the attachment upload API. The API fails to fully validate that provided identifiers—such as boardId, cardId, swimlaneId, and listId—are consistent and refer to a coherent card/board relationship. This flaw enables attackers to upload attachments using mismatched object relationships. The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N), highlighting its network accessibility, low attack complexity, and high integrity impact.
Unauthenticated remote attackers (PR:N) can exploit this issue over the network without user interaction. By supplying inconsistent identifiers during attachment uploads, they bypass intended authorization checks, allowing attachments to be associated with arbitrary boards, cards, swimlanes, or lists. This results in a high integrity impact (I:H), potentially enabling unauthorized data manipulation or pollution within WeKan instances.
Mitigation requires upgrading to WeKan version 8.19 or later, where the issue is addressed via the fix in GitHub commit 1d16955b6d4f0a0282e89c2c1b0415c7597019b8. Further details on the vulnerability and remediation are provided in the VulnCheck advisory at https://www.vulncheck.com/advisories/wekan-attachment-upload-object-relationship-validation-bypass and on the WeKan website at https://wekan.fi/.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5711
Vulnerability details
WeKan versions prior to 8.19 contain an authorization weakness in the attachment upload API. The API does not fully validate that provided identifiers (such as boardId, cardId, swimlaneId, and listId) are consistent and refer to a coherent card/board relationship, enabling…
more
attempts to upload attachments with mismatched object relationships.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Authorization bypass in public-facing WeKan web app directly enables remote exploitation via T1190; resulting ability to associate attachments with arbitrary objects enables stored data manipulation/pollution via T1565.001.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces authorization decisions on attachment-upload API calls to ensure supplied boardId/cardId/swimlaneId/listId values form a valid object relationship before the operation is permitted.
Requires validation of all input parameters (identifiers) to reject inconsistent or incoherent board/card relationships that would otherwise allow unauthorized attachment association.
Enforces information-flow rules between WeKan objects so that an attachment cannot be written to a card or board that is not part of the same authorized relationship.