# CVE-2026-104817: Misskey: Lack of rate limiting and size restrictions in RSS fetching API

> Unauthenticated attackers can exhaust resources and probe internal networks via the RSS fetching API due to missing rate limits and size restrictions.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:L/SI:N/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-4x7v-qx8f-g3p8

## What is CVE-2026-104817?

CVE-2026-104817 is a high-severity server-side request forgery vulnerability in misskey-dev misskey, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Misskey is an open source, federated social media platform. From 12.112.1 until 2026.7.0, the unauthenticated fetch-rss API lacks rate limiting and response-size restrictions and performs synchronous XML parsing. An attacker can trigger unbounded outbound HTTP requests and synchronous parsing, exhausting instance resources, amplifying requests toward third-party servers, or probing network-reachable services even when federation is disabled. This issue is fixed in version 2026.7.0.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-405 (Asymmetric Resource Consumption (Amplification))

## Which versions are affected by CVE-2026-104817?


## How do I fix CVE-2026-104817?

No fix has been published for CVE-2026-104817 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104817 being exploited?

There is no known exploitation of CVE-2026-104817 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104817 and fix it if it is affected.

What it is: CVE-2026-104817 is a high-severity server-side request forgery vulnerability in misskey-dev misskey, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-104817 in the wild and no public exploit code.

Affected product: misskey-dev misskey. 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-2026-104817/ (Markdown: https://insights.sbomify.com/CVE-2026-104817/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104817
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104817
- OSV: https://osv.dev/vulnerability/CVE-2026-104817

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104817/
Summaries are generated and may contain mistakes; the official description above is the record.