CVE-2026-126265
SiYuan 2.1.0 before 3.8.9 CAPTCHA Bypass via Stale Login Cookie
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
SiYuan 2.1.0 before 3.8.9 contains a flaw where the loginAuth CAPTCHA challenge lives in a signed client-side cookie, allowing reuse of a solved challenge. Attackers can replay the original signed siyuan cookie with distinct wrong access codes to brute-force the code and gain an administrator session.
| CWE | CWE-307 |
| Vendor | siyuan-note |
| Product | siyuan |
| Published | Nov 13, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
siyuan-note / siyuan
2.1.0 < 3.8.9
References
Credits
🔍 rexpository