CVE-2026-91973
Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 15, 2026
- Updated
- Sep 15, 2026
- Reserved
- Sep 15, 2026
Description
Vikunja before 2.6.0 contains an authentication bypass vulnerability in CalDAV BasicAuth endpoints that lack rate limiting protection. Remote unauthenticated attackers can issue unbounded credential-guessing requests against /dav, /.well-known, and /feeds routes to bypass the instance's anti-brute-force controls and compromise password-only accounts.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | 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 | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-307 Improper Restriction of Excessive Authentication Attempts
Affected Products
| Product | Versions |
|---|---|
vikunjago-vikunja |
|
References
- GitHub Security Advisory (GHSA-m469-88xx-8rx2)vendor-advisory
- VulnCheck Advisory: Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuththird-party-advisory
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