CVE-2026-34605 SiYuan: Reflected XSS via SVG namespace prefix bypass in SanitizeSVG ( getDynamicIcon, unauthenticated )
An attacker can execute arbitrary JavaScript in a victim's browser via a reflected XSS vulnerability in the unauthenticated dynamic icon endpoint.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-34605?
CVE-2026-34605 is a high-severity cross-site scripting vulnerability in B3log Siyuan, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
SiYuan is a personal knowledge management system. From version 3.6.0 to before version 3.6.2, the SanitizeSVG function introduced in version 3.6.0 to fix XSS in the unauthenticated /api/icon/getDynamicIcon endpoint can be bypassed by using namespace-prefixed element names such as <x:script xmlns:x="http://www.w3.org/2000/svg">. The Go HTML5 parser records the element's tag as "x:script" rather than "script", so the tag check passes it through. The SVG is served with Content-Type: image/svg+xml and no Content Security Policy; when a browser opens the response directly, its XML parser resolves the prefix to the SVG namespace and executes the embedded script. This issue has been patched in version 3.6.2.
Weakness: CWE-79
Which versions are affected by CVE-2026-34605?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260330031106-f09953afc57a |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260330031106-f09953afc57a |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260330031106-f09953afc57a |
Products include B3log Siyuan.
How do I fix CVE-2026-34605?
Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260330031106-f09953afc57a or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-34605 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34605 exists.
Public exploit code: 1 Nuclei template.
Other vulnerabilities in B3log Siyuan
- CVE-2026-32938 SiYuan has an Arbitrary File Read in its Desktop Publish Service
- CVE-2026-33669 SiYuan has Arbitrary Document Reading within the Publishing Service
- CVE-2026-33670 SiYuan has directory traversal within its publishing service
- CVE-2026-32767 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
- CVE-2024-53504 SQL injection in n/a
Sources
Also known as GHSA-73g7-86qr-jrg3, GO-2026-5201.