# CVE-2023-30798: MultipartParser DOS with too many fields or files in Starlette Framework

> An unauthenticated remote attacker can cause denial of service in Starlette by sending excessive form fields or files, leading to memory exhaustion.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Apr 2023
- **Updated:** 15 Jul 2026
- **Also known as:** CLSA-2026-1769040755, DEBIAN-CVE-2023-30798, GHSA-74m5-2c7w-9w3x, PYSEC-2023-48, ROOT-APP-PYPI-CVE-2023-30798, UBUNTU-CVE-2023-30798

## What is CVE-2023-30798?

CVE-2023-30798 is a high-severity denial of service vulnerability in Encode Starlette, published on 21 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

There MultipartParser usage in Encode's Starlette python framework before versions 0.25.0 allows an unauthenticated and remote attacker to specify any number of form fields or files which can cause excessive memory usage resulting in denial of service of the HTTP service.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-30798?

3 open source packages ship an affected version, including starlette. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `starlette` | PyPI | All versions | 0.25.0 |
| `starlette` | PyPI | All versions | 0.25.0 |
| `starlette` | PyPI | All versions | 0.25.0 |

Products: Encode Starlette.

## How do I fix CVE-2023-30798?

Upgrade starlette to 0.25.0 or later.

## Is CVE-2023-30798 being exploited?

There is no known exploitation of CVE-2023-30798 in the wild and no public exploit code.

## Other vulnerabilities in Encode Starlette

- [CVE-2026-48710](https://insights.sbomify.com/CVE-2026-48710/): Kludex Starlette HTTP Request/Response Smuggling (medium 6.5, exploited in the wild)
- [CVE-2026-54283](https://insights.sbomify.com/CVE-2026-54283/): Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS (high 7.5)
- [CVE-2026-48818](https://insights.sbomify.com/CVE-2026-48818/): Starlette: SSRF and NTLM credential theft via UNC paths in StaticFiles on Windows (high 7.5)
- [CVE-2023-29159](https://insights.sbomify.com/CVE-2023-29159/): Starlette has Path Traversal vulnerability in StaticFiles (high 7.5)
- [CVE-2026-48817](https://insights.sbomify.com/CVE-2026-48817/): Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr` (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-30798 and fix it if it is affected.

What it is: CVE-2023-30798 is a high-severity denial of service vulnerability in Encode Starlette, published on 21 Apr 2023. 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-2023-30798 in the wild and no public exploit code.

Affected packages and fixed versions:
- starlette (PyPI): affected all versions; fixed in 0.25.0
- starlette (PyPI): affected all versions; fixed in 0.25.0
- starlette (PyPI): affected all versions; fixed in 0.25.0

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-2023-30798/ (Markdown: https://insights.sbomify.com/CVE-2023-30798/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-30798
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-30798
- OSV: https://osv.dev/vulnerability/CVE-2023-30798

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-30798/
Summaries are generated and may contain mistakes; the official description above is the record.