{"id":"CVE-2026-100635","aliases":[],"title":"SiYuan before v3.8.4 Authentication Bypass via Plaintext Session Cookie","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"siyuan-note","name":"siyuan","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"3.8.4","versionType":"semver"},{"version":"3.8.4","status":"unaffected","versionType":"semver"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-100635"}],"remediation":[],"description":"SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections. An on-path attacker can observe a valid publish-visitor-session-id cookie from a Basic Auth exchange and replay it to access authenticated publish endpoints without knowing the account password.","severity":"high","score":8.2,"published":"2026-09-26T13:23:09.854Z","modified":"2026-10-27T01:30:29.704Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m","https://github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682","https://github.com/siyuan-note/siyuan/commit/ff4d215f78a8d6e6db6052be18b5f9f4db9c7d68","https://www.vulncheck.com/advisories/siyuan-before-3.8.4-authentication-bypass-via-plaintext-session-cookie"],"sources":[{"name":"CVE","id":"CVE-2026-100635","modified":"2026-10-27T01:30:29.704Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-100635"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","score":8.2},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","score":5.9}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T16:45:33.316Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}