CVE-2026-91983

5.3 MEDIUM 0.3% exploit odds Fix listed Auth & access

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. Limited direct impact.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-09-15 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-16 20:16 UTC Last updatedMost recent change to the record

Details

Published: 2026-09-15 16:17 UTC
Last modified: 2026-09-16 20:16 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-863 · Incorrect authorization
Record status: Deferred

Attack profile CVSS 4.0 · 5.3

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: Low
User interaction: None
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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Fix and advisories

References

NVD record · CVE.org record