{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56765","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-06-22T21:55:17.942Z","datePublished":"2026-07-10T13:57:59.648Z","dateUpdated":"2026-07-10T17:00:55.985Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-07-10T13:57:59.648Z"},"datePublic":"2026-03-23T00:00:00.000Z","title":"Vikunja - Unauthenticated Instance-Wide Data Breach via Link Share Hash Disclosure Chained with Cross-Project Attachment IDOR","descriptions":[{"lang":"en","value":"Vikunja before 2.2.1 contains an authorization flaw where the LinkSharing.ReadAll endpoint exposes share hashes to users with read access, enabling permission escalation to admin-level shares. The GetTaskAttachment endpoint performs permission checks against user-supplied task IDs but fetches attachments by sequential ID without verifying ownership, allowing attackers to download and delete all file attachments across all projects instance-wide."}],"problemTypes":[{"descriptions":[{"lang":"en","description":"Authorization Bypass Through User-Controlled Key","cweId":"CWE-639","type":"CWE"}]}],"affected":[{"vendor":"Vikunja","product":"Vikunja","defaultStatus":"unaffected","packageURL":"pkg:golang/code.vikunja.io/api","versions":[{"version":"0","status":"affected","versionType":"semver","lessThan":"2.2.1"},{"version":"2.2.1","status":"unaffected","versionType":"semver"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*","versionEndExcluding":"2.2.1"}]}]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":9.3,"baseSeverity":"CRITICAL"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":9.8,"baseSeverity":"CRITICAL"}}],"references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j","name":"GitHub Security Advisory (GHSA-2pv8-4c52-mf8j)","tags":["vendor-advisory"]},{"name":"VulnCheck Advisory: Vikunja - Unauthenticated Instance-Wide Data Breach via Link Share Hash Disclosure Chained with Cross-Project Attachment IDOR","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/vikunja-unauthenticated-instance-wide-data-breach-via-link-share-hash-disclosure-chained-with-cross-project-attachment-idor"}],"credits":[{"lang":"en","value":"offset","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-10T16:40:04.075201Z","id":"CVE-2026-56765","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-10T17:00:55.985Z"}}]}}