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CVE-2026-91981— Vikunja before 2.6.0 User Enumeration via v2 API

Quick assessment

Affected
go-vikunja vikunja
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Vikunja 2.6.0 之前的版本中，v2 API 中的用户搜索端点未能正确验证链接共享令牌。拥有只读共享链接的攻击者可以通过项目端点枚举项目用户，并通过全局搜索端点确认任意用户名是否存在。

CVSS 4.3 · Medium

Possible ATT&CK Techniques 2 AI

T1207 · Rogue Domain Controller T1079
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I. Basic Information for CVE-2026-91981

Vulnerability Information
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Vulnerability Title
Vikunja before 2.6.0 User Enumeration via v2 API
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
信息暴露
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
go-vikunja vikunja 0 ~ 2.6.0 -

II. Public POCs for CVE-2026-91981

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III. Intelligence Information for CVE-2026-91981

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Vendor Advisories for CVE-2026-91981 (2)

Same Patch Batch · go-vikunja · 2026-09-15 · 13 CVEs total

CVE-2026-91972 7.5 HIGH Vikunja before 2.6.0 Authentication Bypass via Unthrottled API
CVE-2026-91985 7.5 HIGH Vikunja before 2.6.0 Privilege Escalation via Link Share Hash
CVE-2026-91973 7.5 HIGH Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth
CVE-2026-91968 6.5 MEDIUM vikunja before 2.6.0 Denial of Service via unbounded filter recursion
CVE-2026-91971 6.5 MEDIUM Vikunja before 2.6.0 Denial of Service via Avatar Upload
CVE-2026-91979 6.5 MEDIUM Vikunja before 2.6.0 Denial of Service via Decompression Bomb
CVE-2026-91970 6.5 MEDIUM Vikunja before 2.6.0 Resource Exhaustion via Planka Migration
CVE-2026-91969 6.5 MEDIUM vikunja before 2.6.0 Resource Exhaustion via CSV Migration
CVE-2026-91982 4.3 MEDIUM Vikunja before 2.6.0 TOTP Secret Disclosure via API
CVE-2026-91980 4.3 MEDIUM vikunja before 2.6.0 Team Enumeration via Project Share
CVE-2026-91983 4.3 MEDIUM Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter
CVE-2026-91984 4.3 MEDIUM Vikunja before 2.6.0 Broken Object-Level Authorization via task-position

IV. Related Vulnerabilities

Same product: vikunja
Same vendor: go-vikunja
Same weakness: CWE-200

V. Comments for CVE-2026-91981

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