Authenticated team-roster disclosure via unchecked team IDs
Published Sep 15, 2026 · Updated Sep 15, 2026
Authorization bypass in Vikunja before 2.6.0 allows remote authenticated users to read every team's full member roster through the project teams API. The project-team attachment handler accepts arbitrary team IDs after checking only project administration, and the listing handler returns full team objects without rechecking team visibility. An ordinary account and an attacker-owned project are sufficient to enumerate names, descriptions, usernames, display names, and membership admin flags instance-wide.
Summary
What happened
Authorization bypass in Vikunja before 2.6.0 allows remote authenticated users to read every team's full member roster through the project teams API. The project-team attachment handler accepts arbitrary team IDs after checking only project administration, and the listing handler returns full team objects without rechecking team visibility. An ordinary account and an attacker-owned project are sufficient to enumerate names, descriptions, usernames, display names, and membership admin flags instance-wide.
The record
- CVE
- CVE-2026-91980
- Published
- Sep 15, 2026
- Updated
- Sep 15, 2026
- Vendor
- Vikunja
- Product
- Vikunja
- Classifications
- CWE-200, CWE-639, T1087, T1069
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 15, 2026CVE publishedPublication date reported by the CVE source.
- Sep 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <2.6.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-39p5-2wrr-xh29 proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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