Skip to content
Noroxi
CVE-2026-40922· NVD / CVE Program· CNA GitHub_M

SiYuan: Incomplete sanitization of bazaar README allows stored XSS via iframe srcdoc (incomplete fix for CVE-2026-33066)

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.37% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: siyuan-note siyuan 3.6.4.

Low priority for now. Upgrade to siyuan-note siyuan 3.6.4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.3 · v4.0—No exploit Fix available
Published
Apr 16, 2026
Updated
Jun 17, 2026
EPSS
0.3% · 30th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-40922

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for b3log records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
b3logsiyuan

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • b3log siyuan3.6.1 and later · before 3.6.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • siyuan-note siyuan

    • < 3.6.4affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Gogithub.com/siyuan-note/siyuan/kernelbefore 0.0.0-20260314111550-b382f50e18800.0.0-20260314111550-b382f50e1880
Gogithub.com/siyuan-note/siyuan/kernelbefore 0.0.0-20260414013942-62eed37a32630.0.0-20260414013942-62eed37a3263

Same product

b3log: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-32767SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
    39Monitor
  • CVE-2026-30869SiYuan has a Path Traversal in /export Endpoint Allows Arbitrary File Read and Secret Leakage
    39Monitor
  • CVE-2024-53507A SQL injection vulnerability was discovered in Siyuan 3.1.11 in /getHistoryItems.
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-40259Apr 16, 2026 · SiYuan: Publish Reader Can Arbitrarily Delete Attribute View Files via removeUnusedAttributeView API
    32Monitor
  • ← EarlierCVE-2026-40318Apr 16, 2026 · SiYuan: Publish Reader Path Traversal Delete via `removeUnusedAttributeView`
    34Monitor
  • ← EarlierCVE-2026-40322Apr 16, 2026 · SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE
    36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
siyuan-note siyuan3.6.4 · descriptionVendor (CNA)
Go:github.com/siyuan-note/siyuan/kernel0.0.0-20260314111550-b382f50e1880Package registry (OSV)
Go:github.com/siyuan-note/siyuan/kernel0.0.0-20260414013942-62eed37a3263Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-403220 days apartSiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE
    36Monitor
  • CVE-2026-398469 days apartSiYuan affected by Remote Code Execution in the Electron desktop client via stored XSS in synced table captions
    36Monitor
  • CVE-2026-3444816 days apartSiYuan: Stored XSS in Attribute View gallery/kanban cover rendering allows arbitrary command execution in the desktop client
    36Monitor
  • CVE-2026-3460516 days apartSiYuan: Reflected XSS via SVG namespace prefix bypass in SanitizeSVG ( getDynamicIcon, unauthenticated )
    34Monitor
  • CVE-2026-3458516 days apartSiYuan: Stored XSS in imported .sy.zip content leads to arbitrary command execution
    32Monitor
  • CVE-2026-3180737 days apartSiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS
    25Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records