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CVE-2026-91973 Details

ANALYZED

This CVE record has been analyzed and enriched by NVDAPI.com as an independent party.

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:7.4 HIGHVector:CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CNA: [email protected]CVSS-B:7.5 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/go-vikunja/vikunja/security/advisories/GHSA-m469-88xx-8rx2	CISA-ADP	AdvisoryRemedyVendor
https://github.com/go-vikunja/vikunja/security/advisories/GHSA-m469-88xx-8rx2	[email protected]	AdvisoryRemedyVendor
https://www.vulncheck.com/advisories/vikunja-before-2.6.0-authentication-bypass-via-caldav-basicauth	[email protected]	Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-307	Improper Restriction of Excessive Authentication Attempts	[email protected]

Affected Products

Product	Versions
Vikunja	<= 2.5.0 (semver)
CPE No CPEs found in CPE dictionary for this product. Remediation Upgrade: 2.6.0moderate effort

Change History

2 change records found show changes

Date	Action	Recorded By
Sep 15, 2026	New CVE Received	[email protected]
Sep 15, 2026	CVE Modified	CISA-ADP