{"id":"CVE-2026-73056","state":"PUBLISHED","title":"SiYuan kernel before 3.7.4 Unthrottled Brute-Force via API Token","description":"SiYuan kernel versions before 3.7.4 contain an improper restriction of excessive authentication attempts vulnerability in the CheckAuth() middleware. The middleware accepts the API token (Conf.Api.Token) via an Authorization header (Token/Bearer) or a ?token= query parameter, and neither path is protected by the application's CAPTCHA/lockout mechanism (NeedCaptcha/WrongAuthCount). As a result, an unauthenticated remote attacker can perform unlimited automated guesses of the API token, particularly when a short or weak custom token has been configured, and upon success gains full RoleAdministrator access enabling arbitrary file operations and SQL queries.","publishedAt":"2026-08-16T13:14:04.660Z","updatedAt":"2026-08-17T18:33:37.963Z","severity":{"score":9.3,"label":"Critical","version":"4.0","vector":"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","source":"VulnCheck"},"assigner":"VulnCheck","products":["siyuan-note siyuan"],"affected":[{"vendor":"siyuan-note","product":"siyuan","packageURL":"pkg:golang/github.com/siyuan-note/siyuan/kernel","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.7.4","versionType":"semver"},{"version":"3.7.4","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/siyuan-note/siyuan/security/advisories/GHSA-m6w6-p7pc-fpg2","https://www.vulncheck.com/advisories/siyuan-kernel-before-unthrottled-brute-force-via-api-token"],"weaknesses":["CWE-307"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/73xxx/CVE-2026-73056.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-73056","state":"PUBLISHED","datePublished":"2026-08-16T13:14:04.660Z","dateUpdated":"2026-08-17T18:33:37.963Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-08-10T19:10:18.101Z"},"containers":{"cna":{"title":"SiYuan kernel before 3.7.4 Unthrottled Brute-Force via API Token","descriptions":[{"lang":"en","value":"SiYuan kernel versions before 3.7.4 contain an improper restriction of excessive authentication attempts vulnerability in the CheckAuth() middleware. The middleware accepts the API token (Conf.Api.Token) via an Authorization header (Token/Bearer) or a ?token= query parameter, and neither path is protected by the application's CAPTCHA/lockout mechanism (NeedCaptcha/WrongAuthCount). As a result, an unauthenticated remote attacker can perform unlimited automated guesses of the API token, particularly when a short or weak custom token has been configured, and upon success gains full RoleAdministrator access enabling arbitrary file operations and SQL queries."}],"affected":[{"vendor":"siyuan-note","product":"siyuan","packageURL":"pkg:golang/github.com/siyuan-note/siyuan/kernel","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.7.4","versionType":"semver"},{"version":"3.7.4","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-m6w6-p7pc-fpg2","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-m6w6-p7pc-fpg2)"},{"url":"https://www.vulncheck.com/advisories/siyuan-kernel-before-unthrottled-brute-force-via-api-token","name":"VulnCheck Advisory: SiYuan kernel before 3.7.4 Unthrottled Brute-Force via API Token","tags":["third-party-advisory"]}],"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-307","lang":"en","description":"Improper Restriction of Excessive Authentication Attempts","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-16T13:14:04.660Z"},"datePublic":"2026-08-02T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*","versionEndExcluding":"3.7.4"}]}]}],"credits":[{"lang":"en","value":"alham-rizvi","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-m6w6-p7pc-fpg2","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-17T18:33:21.865800Z","id":"CVE-2026-73056","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-17T18:33:37.963Z"}}]}}}