{"id":"CVE-2026-68581","state":"PUBLISHED","title":"Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision","description":"Vikunja versions 0.22.0 through 2.3.0 fail to validate the principal type in API token management. Because user IDs and link-share IDs are independent numeric sequences and both resolve through a generic web.Auth.GetID() interface, a link-share JWT whose numeric ID equals a target user's ID is treated as that user by the /api/v1/tokens endpoints. An authenticated attacker can obtain a target's numeric user ID via authenticated user search, then create link shares on an attacker-writable project until the link-share sequence reaches that value, and use the resulting link-share JWT to list, create, and delete the target user's API tokens (including issuing a new token with attacker-chosen scopes under the target's permissions). Fixed in version 2.4.0.","publishedAt":"2026-08-02T12:15:27.893Z","updatedAt":"2026-08-03T15:02:40.435Z","severity":{"score":8.6,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["go-vikunja vikunja"],"affected":[{"vendor":"go-vikunja","product":"vikunja","packageURL":"pkg:golang/code.vikunja.io/api","defaultStatus":"unaffected","versions":[{"version":"0.22.0","status":"affected","lessThan":"2.4.0","versionType":"semver"}]}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-vvcv-vpph-h844","https://github.com/go-vikunja/vikunja/commit/e6b25bd57b537ef9a72b5acdadf446ca5ef77bfa","https://github.com/go-vikunja/vikunja/commit/95b7e673fb5ee407498fa4b13e8b4c57847a4a0b","https://www.vulncheck.com/advisories/vikunja-through-authentication-bypass-via-principal-id-collision"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68581.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68581","state":"PUBLISHED","datePublished":"2026-08-02T12:15:27.893Z","dateUpdated":"2026-08-03T15:02:40.435Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-07-31T11:56:29.760Z"},"containers":{"cna":{"title":"Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision","descriptions":[{"lang":"en","value":"Vikunja versions 0.22.0 through 2.3.0 fail to validate the principal type in API token management. Because user IDs and link-share IDs are independent numeric sequences and both resolve through a generic web.Auth.GetID() interface, a link-share JWT whose numeric ID equals a target user's ID is treated as that user by the /api/v1/tokens endpoints. An authenticated attacker can obtain a target's numeric user ID via authenticated user search, then create link shares on an attacker-writable project until the link-share sequence reaches that value, and use the resulting link-share JWT to list, create, and delete the target user's API tokens (including issuing a new token with attacker-chosen scopes under the target's permissions). Fixed in version 2.4.0."}],"affected":[{"vendor":"go-vikunja","product":"vikunja","packageURL":"pkg:golang/code.vikunja.io/api","defaultStatus":"unaffected","versions":[{"version":"0.22.0","status":"affected","lessThan":"2.4.0","versionType":"semver"}]}],"references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-vvcv-vpph-h844","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-vvcv-vpph-h844)"},{"url":"https://github.com/go-vikunja/vikunja/commit/e6b25bd57b537ef9a72b5acdadf446ca5ef77bfa","tags":["patch"],"name":"Patch Commit"},{"url":"https://github.com/go-vikunja/vikunja/commit/95b7e673fb5ee407498fa4b13e8b4c57847a4a0b","tags":["patch"],"name":"Patch Commit"},{"url":"https://www.vulncheck.com/advisories/vikunja-through-authentication-bypass-via-principal-id-collision","name":"VulnCheck Advisory: Vikunja 0.22.0 through 2.3.0 Authentication Bypass via Principal ID Collision","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.6,"baseSeverity":"HIGH"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE","baseScore":8.1,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-03T11:03:03.486Z"},"datePublic":"2026-07-19T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*","versionStartIncluding":"0.22.0","versionEndExcluding":"2.4.0"}]}]}],"credits":[{"lang":"en","value":"ryuyunseong","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-vvcv-vpph-h844","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-03T15:00:37.506412Z","id":"CVE-2026-68581","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-03T15:02:40.435Z"}}]}}}