{"answers":{"affected":"3 open source packages ship an affected version, including code.vikunja.io/api.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91973 exists.","fix":"Upgrade code.vikunja.io/api to 2.6.0 or later.","what":"CVE-2026-91973 is a high-severity authentication bypass vulnerability in go-vikunja vikunja, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-91973 and fix it if it is affected.\n\nWhat it is: CVE-2026-91973 is a high-severity authentication bypass vulnerability in go-vikunja vikunja, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91973 exists.\n\nAffected packages and fixed versions:\n- code.vikunja.io/api (Go): affected all versions; no fix listed\n- code.vikunja.io/api (Go): affected all versions; fixed in 2.6.0\n- code.vikunja.io/api (Go): affected all versions; fixed in 2.6.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-91973/ (Markdown: https://insights.sbomify.com/CVE-2026-91973/index.md)","id":"CVE-2026-91973","markdown":"https://insights.sbomify.com/CVE-2026-91973/index.md","name":"CVE-2026-91973","record":{"aliases":["GHSA-m469-88xx-8rx2","GO-2026-6737"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["account_takeover"],"network_reachable":"yes","non_default_config":false,"product_category":"Vikunja task manager","requires_auth":"none","summary":"Remote attackers can bypass anti-brute-force controls on CalDAV endpoints to guess passwords and compromise accounts in Vikunja.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":8.7,"severity":"high","source":"cna","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","version":"4.0"},"cwes":[{"id":"CWE-307","name":"Improper Restriction of Excessive Authentication Attempts"}],"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.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Vikunja before 2.6.0 Authentication Bypass via CalDAV BasicAuth","id":"CVE-2026-91973","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":3,"n_references":2,"next":{"headline":"Vikunja before 2.6.0 Denial of Service via Decompression Bomb","id":"CVE-2026-91979"},"packages":[{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"code.vikunja.io/api","purl":"pkg:golang/code.vikunja.io/api","source":"GO-2026-6737"},{"ecosystem":"Go","fixed":["2.6.0"],"introduced":["0"],"last_affected":[],"package":"code.vikunja.io/api","purl":null,"source":"GHSA-m469-88xx-8rx2"},{"ecosystem":"Go","fixed":["2.6.0"],"introduced":["0"],"last_affected":[],"package":"code.vikunja.io/api","purl":"pkg:golang/code.vikunja.io/api","source":"GHSA-m469-88xx-8rx2"}],"prev":{"headline":"Vikunja before 2.6.0 Authentication Bypass via Unthrottled API","id":"CVE-2026-91972"},"products":["vikunja"],"published":"2026-09-15","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-15","vendors":["go-vikunja"]},"summary":"Remote attackers can bypass anti-brute-force controls on CalDAV endpoints to guess passwords and compromise accounts in Vikunja.","url":"https://insights.sbomify.com/CVE-2026-91973/"}