{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-91985", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-09-15T11:10:41.354Z", "datePublished": "2026-09-15T15:18:28.282Z", "dateUpdated": "2026-09-15T16:04:15.007Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-15T15:18:28.282Z"}, "datePublic": "2026-08-31T00:00:00.000Z", "title": "Vikunja before 2.6.0 Privilege Escalation via Link Share Hash", "descriptions": [{"lang": "en", "value": "Vikunja before 2.6.0 fails to properly restrict access to the link-share hash field in single-share read endpoints, allowing read-only members to obtain the share's secret credential. Attackers can exchange the disclosed hash for a link-share JWT at the share's permission level to escalate privileges and perform unauthorized writes or administrative actions."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Exposure of Sensitive Information to an Unauthorized Actor", "cweId": "CWE-200", "type": "CWE"}]}], "affected": [{"vendor": "go-vikunja", "product": "vikunja", "defaultStatus": "unaffected", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThan": "2.6.0"}, {"version": "2.6.0", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:vikunja:vikunja:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.6.0"}]}]}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 8.7, "baseSeverity": "HIGH", "exploitMaturity": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS"}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "format": "CVSS"}], "references": [{"url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-qfwc-vx6f-3g6g", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-qfwc-vx6f-3g6g)"}, {"name": "VulnCheck Advisory: Vikunja before 2.6.0 Privilege Escalation via Link Share Hash", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/vikunja-before-2.6.0-privilege-escalation-via-link-share-hash"}], "credits": [{"lang": "en", "value": "ybsun0215", "type": "reporter"}, {"lang": "en", "value": "JellowBeanz26", "type": "reporter"}, {"lang": "en", "value": "0xcelien", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}, "adp": [{"references": [{"url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-qfwc-vx6f-3g6g", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-15T16:03:46.456174Z", "id": "CVE-2026-91985", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-15T16:04:15.007Z"}}]}}

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