HOMEVULNERABILITIESCVE-2026-40922
MEDIUM

CVE-2026-40922

CWE-79Published: April 17, 2026· Updated: Apr 20, 2026

5.4
CVSS v3.1
EPSS:0.03%probability of exploitation in 30 daysPercentile:10.2th

Official 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.

NVD Source

Technical Analysis

CVE-2026-40922 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionRequired
ScopeChanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected Vendors & Products

b3log1 product
siyuan
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428
ADVISORYhttps://github.com/advisories/GHSA-4663-4mpg-879v
ADVISORYhttps://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jg
ADVISORYhttps://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jg

All References (5)

→
https://github.com/advisories/GHSA-4663-4mpg-879vThird Party Advisory
→
https://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428Patch
→
https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4Release Notes
→
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jgExploit · Third Party Advisory
→
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jgExploit · Third Party Advisory

Quick Facts

CVE IDCVE-2026-40922
CVSS Score5.4 / 10
SeverityMEDIUM
WeaknessCWE-79
CISA KEVNo
EPSS (30d)0.03%
Affected1 vendor
PublishedApr 17, 2026

Related CVEs (CWE-79)

CVE-2026-40470
9.9
CVE-2026-54158
9.9
CVE-2026-50551
9.9
CVE-2026-40472
9.9
CVE-2026-54067
9.9
CVE-2025-14320
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2026-40922 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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