{"id":"CVE-2026-100635","title":"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","summary":"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 p…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-319"],"vendor":"siyuan-note","product":"siyuan","affected":["siyuan < 3.8.4"],"published":"2026-09-26","updated":"2026-10-08","sourceUpdated":"2026-10-08T16:16:57.570","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100635","references":[{"url":"https://github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682","label":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/commit/ff4d215f78a8d6e6db6052be18b5f9f4db9c7d68","label":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/siyuan-before-3.8.4-authentication-bypass-via-plaintext-session-cookie","label":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-28T18:53:29.876873Z"},"epss":0.00327,"epssPercentile":0.25659,"ingestedAt":"2026-09-26T13:33:20.925Z","slug":"CVE-2026-100635","body":"## Overview\n\nSiYuan 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":212103,"id":"CVE-2026-100635","ts":1790623191925,"field":"exploit_available","old":"false","new":"true"}]}