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VulnerabilityPublished Updated

CVE-2026-40922: siyuan · Cross-site Scripting

Affects siyuanSource CVE Database V5

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Mentioned vulnerabilities

Not known to be exploited · CVSS 5.3 Medium : upgrade to 3.6.4 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.6.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade siyuan and siyuan-note/siyuan to 3.6.4.

Affected software

ProductAffectedFixed in
siyuan-notesiyuanAffected
  • <3.6.4
Fixed in
  • 3.6.4
GitHubsiyuan-note/siyuanpkg:github/siyuan-note/siyuanOther threatsAffected
  • <3.6.4
Fixed in
  • 3.6.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade SiYuan to version 3.6.4 or later, where this vulnerability has been fixed. Since the vendor advisory indicates the issue is resolved in 3.6.4, applying this official fix is the recommended remediation. No additional mitigations are specified.

Description

SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan's marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user's machine. This issue has been fixed in version 3.6.4.

References

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