CVE-2026-126265
SiYuan 2.1.0 before 3.8.9 CAPTCHA Bypass via Stale Login Cookie
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| siyuan siyuan-note github.com/siyuan-note/siyuan/kernel
golang |
≥ 2.1.0; < 3.8.9 (affected, semver) 3.8.9 (unaffected, semver) Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 9.1 critical |
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 7.4 high |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-23g4-vqq8-5764CNA: VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/siyuan-2.1.0-before-3.8.9-captcha-bypass-via-stale-login-cookieCNA: VulnCheck · third-party-advisory
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