CVE-2026-34605Public exploitNetwork attack vector

Reflected XSS via SVG namespace-prefix sanitizer bypass

Published Mar 31, 2026 · Updated Mar 31, 2026

Reflected XSS in SiYuan 3.6.0 through 3.6.1 allows remote attackers to execute script at the server origin via a crafted icon URL. The unauthenticated getDynamicIcon route inserts content into SVG, and SanitizeSVG compares qualified names such as x:script without stripping the namespace prefix. Exploitation requires a user to open the URL directly; the resulting same-origin script can read notes or modify settings through the user's session.

CVSS severity8.6
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in SiYuan 3.6.0 through 3.6.1 allows remote attackers to execute script at the server origin via a crafted icon URL. The unauthenticated getDynamicIcon route inserts content into SVG, and SanitizeSVG compares qualified names such as x:script without stripping the namespace prefix. Exploitation requires a user to open the URL directly; the resulting same-origin script can read notes or modify settings through the user's session.

The record

CVE
CVE-2026-34605
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
SiYuan Note
Product
SiYuan
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.6.0, < 3.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SiYuan Note · SiYuanversion=>= 3.6.0, < 3.6.2

Published CVSS scores

8.6GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
6.1NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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