CVE-2026-91973
CVSS v3
7.5
HIGH
EPSS Score
0.7 %
exploit probability, as of 2026-09-28
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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.
Technical details
- Published
- 2026-09-15
- Last Modified
- 2026-09-16
Frequently asked questions
What is CVE-2026-91973?
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.
Is CVE-2026-91973 actively exploited?
Active exploitation of CVE-2026-91973 has not been confirmed. Its EPSS score was 0.7% on 2026-09-28, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2026-91973?
CVE-2026-91973 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2026-91973 affecting your environment?
Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.
No credit card required · 500 free checks/month · Free API key
Other 2026 vulnerabilities worth triaging
Ranked by exploit probability (EPSS).
- CVE-2026-10520KEV
- CVE-2026-24061KEV
- CVE-2026-1281KEV
- CVE-2026-1340KEVUnauthenticated Remote Code Execution via Code Injection in Ivanti Endpoint Manager Mobile
- CVE-2026-41940KEV
- CVE-2026-23760KEVSmarterTools SmarterMail < Build 9511 Authentication Bypass via Password Reset API
- CVE-2026-21643KEVSQL Injection Vulnerability in FortiClientEMS 7.4.4 Allows Unauthenticated Remote Code Execution
- CVE-2026-20182KEV