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CVE-2026-91983— Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter

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.

Vikunja 在 2.6.0 之前的版本中存在一个 API 令牌权限范围（scope）绕过漏洞，位于任务读取接口中，授权逻辑未能检查查询字符串参数。拥有受限令牌权限的攻击者可以利用 参数，绕过适当的权限校验，访问受限数据，例如评论、反应（reactions）和时间记录。

CVSS 4.3 · Medium

Possible ATT&CK Techniques 1 AI

T1078 · Valid Accounts
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I. Basic Information for CVE-2026-91983

Vulnerability Information
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Vulnerability Title
Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter
Source: CVE Program / CVE List V5
Vulnerability Description
Vikunja before 2.6.0 contains an API token scope bypass vulnerability in task read endpoints where authorization fails to inspect query string parameters. Attackers with limited token scopes can use the expand parameter to access restricted data like comments, reactions, and time entries without proper permission verification.
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
授权机制不正确
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
go-vikunja vikunja 1.0.0 ~ 2.6.0 -

II. Public POCs for CVE-2026-91983

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III. Intelligence Information for CVE-2026-91983

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Vendor Advisories for CVE-2026-91983 (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-2026-91981 4.3 MEDIUM Vikunja before 2.6.0 User Enumeration via v2 API
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-863

V. Comments for CVE-2026-91983

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