Is CVE-2026-109310 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-109310 being exploited in the wild.

How severe is CVE-2026-109310?

Medium severity, with a CVSS score of 6.5, published 12 October 2026.

Is there a fix for CVE-2026-109310?

Yes: fixed in v3.8.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-109310 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-109310?

Check whether you run SiYuan at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-109310: SiYuan resource exhaustion in getDynamicIcon template

CVE-2026-109310 · Severity: medium · CVSS 6.5 · Published 2026-10-12

SiYuan is a note-taking and knowledge management application that supports publishing workspaces to the internet. The /api/icon/getDynamicIcon endpoint allows publish readers to supply template code that is processed using the Sprig template function library without proper restrictions. An attacker can invoke unbounded functions like until() to allocate arbitrary amounts of memory in a single request, exhausting the server and crashing the kernel, taking down both the published site and the owner's workspace.

Technologies: SiYuan. Vendors: SiYuan.

Quick answers

Is CVE-2026-109310 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-109310 being exploited in the wild.
How severe is CVE-2026-109310?: Medium severity, with a CVSS score of 6.5, published 12 October 2026.
Which products and versions are affected?: SiYuan v3.1.12 before v3.8.6.
Is there a fix for CVE-2026-109310?: Yes: fixed in v3.8.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-109310 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-109310?: Check whether you run SiYuan at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: v3.8.6

Technical details

The /api/icon/getDynamicIcon endpoint parses the content query parameter as a Go text/template using Sprig's TxtFuncMap with only three functions removed (env, expandenv, getHostByName). The uncapped until(n) function allocates memory without bounds—a single request can exhaust gigabytes of RAM. Attack requires only publish reader credentials (or none if publish auth is disabled), and allocation scales linearly with the integer parameter chosen by the caller.

Affected products

SiYuan SiYuan v3.1.12 before v3.8.6

Timeline

2026-09-24: disclosed
2026-10-12: advisory

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.