# CVE-2026-91985

## Summary

- **CVE ID:** CVE-2026-91985
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-200
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 15, 2026

## Description

Vikunja before 2.6.0 fails to properly restrict access to the link-share hash field in single-share read endpoints, allowing read-only members to obtain the share's secret credential. Attackers can exchange the disclosed hash for a link-share JWT at the share's permission level to escalate privileges and perform unauthorized writes or administrative actions.

## Affected Products

- go-vikunja — vikunja (0)
- go-vikunja — vikunja (2.6.0)

## References

- [CNA](https://github.com/go-vikunja/vikunja/security/advisories/GHSA-qfwc-vx6f-3g6g)
- [CNA](https://www.vulncheck.com/advisories/vikunja-before-2.6.0-privilege-escalation-via-link-share-hash)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.38%
- **EPSS Percentile:** 31.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._