# CVE-2026-85585: SiYuan before v3.8.2 Unbounded Memory Consumption via ControlConcurrency

> Unauthenticated attackers can cause denial of service in SiYuan by sending numerous unique request paths to exhaust memory and synchronization resources.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** GHSA-p59v-3q54-qq55, GHSA-w2pg-pc8x-qj83

## What is CVE-2026-85585?

CVE-2026-85585 is a high-severity denial of service vulnerability in siyuan-note siyuan, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SiYuan before v3.8.2 contains an unbounded resource consumption vulnerability in the request-concurrency middleware that retains mutex entries for every unique request path without eviction. Unauthenticated attackers can send numerous unique request paths to permanently increase process memory and synchronization overhead, degrading availability.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-85585?


## How do I fix CVE-2026-85585?

No fix has been published for CVE-2026-85585 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85585 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85585 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85585 and fix it if it is affected.

What it is: CVE-2026-85585 is a high-severity denial of service vulnerability in siyuan-note siyuan, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85585 exists.

Affected product: siyuan-note siyuan. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-85585/ (Markdown: https://insights.sbomify.com/CVE-2026-85585/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85585
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85585
- OSV: https://osv.dev/vulnerability/CVE-2026-85585

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85585/
Summaries are generated and may contain mistakes; the official description above is the record.