{"id":"CVE-2026-91973","revision":"5251f86b8ecc4db29cb54e0f1c086566","records":[{"revision":"5251f86b8ecc4db29cb54e0f1c086566","observedAt":"2026-10-25T16:19:22.228+00:00","statement":{"source":"nvd","id":"CVE-2026-91973","aliases":[],"title":"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-kn…","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.","state":0,"publishedAt":"2026-09-15T16:17:54.23+00:00","modifiedAt":"2026-09-16T20:16:09.343+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · disclosure@vulncheck.com · Secondary","vector":"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/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","score":8.7,"severity":"HIGH"},{"system":"CVSS 3.1 · disclosure@vulncheck.com · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5,"severity":"HIGH"}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-m469-88xx-8rx2","https://www.vulncheck.com/advisories/vikunja-before-2.6.0-authentication-bypass-via-caldav-basicauth"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-91973","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-307"],"productCriteria":[],"sourceDates":{"published":"2026-09-15T16:17:54.230","lastModified":"2026-09-16T20:16:09.343"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-91973","identifiers":["CVE-2026-91973"]},"retained":false,"historicalAffected":[]}],"coverage":[]}