CVE-2026-91981: Exposure of Sensitive Information to an Unauthorized Actor in go-vikunja vikunja
Vikunja versions before 2.6.0 fail to properly validate link-share tokens in the v2 API user search endpoints. Attackers with a read-only share link can enumerate project users via the projects endpoint and confirm arbitrary usernames exist via the global search endpoint.
AI Analysis
Technical Summary
CVE-2026-91981 describes an information exposure vulnerability in go-vikunja's vikunja product affecting versions prior to 2.6.0. The issue arises from improper validation of link-share tokens in the v2 API user search endpoints. An attacker possessing a read-only share link can enumerate users within projects through the projects endpoint and verify arbitrary usernames using the global search endpoint. This flaw leaks sensitive user information to unauthorized actors without requiring elevated privileges beyond read-only access.
Potential Impact
The vulnerability allows unauthorized actors with read-only share links to enumerate project users and confirm usernames, leading to exposure of sensitive user information. There is no indication of impact on data integrity or availability. The CVSS score of 4.3 reflects a medium severity confidentiality impact with no integrity or availability impact.
Mitigation Recommendations
A fix is available in version 2.6.0. Users should upgrade to vikunja 2.6.0 or later to remediate this vulnerability. No additional mitigations are specified.
CVE-2026-91981: Exposure of Sensitive Information to an Unauthorized Actor in go-vikunja vikunja
Description
Vikunja versions before 2.6.0 fail to properly validate link-share tokens in the v2 API user search endpoints. Attackers with a read-only share link can enumerate project users via the projects endpoint and confirm arbitrary usernames exist via the global search endpoint.
CVSS v3.1
Score 4.3medium
Affected software
go-vikunja
vikunja
pkg:golang/github.com/go-vikunja/vikunjaRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-91981 describes an information exposure vulnerability in go-vikunja's vikunja product affecting versions prior to 2.6.0. The issue arises from improper validation of link-share tokens in the v2 API user search endpoints. An attacker possessing a read-only share link can enumerate users within projects through the projects endpoint and verify arbitrary usernames using the global search endpoint. This flaw leaks sensitive user information to unauthorized actors without requiring elevated privileges beyond read-only access.
Potential Impact
The vulnerability allows unauthorized actors with read-only share links to enumerate project users and confirm usernames, leading to exposure of sensitive user information. There is no indication of impact on data integrity or availability. The CVSS score of 4.3 reflects a medium severity confidentiality impact with no integrity or availability impact.
Mitigation Recommendations
A fix is available in version 2.6.0. Users should upgrade to vikunja 2.6.0 or later to remediate this vulnerability. No additional mitigations are specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-15T11:10:41.353Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aa9651c55bf5e2cf502eb29
Added to database: 09/15/2026, 15:32:44 UTC
Last enriched: 09/15/2026, 15:47:25 UTC
Last updated: 09/16/2026, 02:32:36 UTC
Views: 7
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