# CVE-2026-30974: Copyparty volflag `nohtml` did not block javascript in svg files

> Attackers can execute JavaScript via SVG uploads in Copyparty when the nohtml security feature is enabled, potentially compromising other users.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 10 Mar 2026
- **Updated:** 11 Mar 2026
- **Also known as:** GHSA-m6hv-x64c-27mm, PYSEC-2026-2137

## What is CVE-2026-30974?

CVE-2026-30974 is a medium-severity cross-site scripting vulnerability in 9001 copyparty, published on 10 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Copyparty is a portable file server. Prior to v1.20.11., the nohtml config option, intended to prevent execution of JavaScript in user-uploaded HTML files, did not apply to SVG images. A user with write-permission could upload an SVG containing embedded JavaScript, which would execute in the context of whichever user opens it. This has been fixed in v1.20.11.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-30974?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `copyparty` | PyPI | All versions | 1.20.11 |
| `copyparty` | PyPI | All versions | 1.20.11 |
| `copyparty` | PyPI | All versions | 1.20.11 |

Products: 9001 Copyparty.

## How do I fix CVE-2026-30974?

Upgrade copyparty to 1.20.11 or later.

## Is CVE-2026-30974 being exploited?

There is no known exploitation of CVE-2026-30974 in the wild and no public exploit code.

## Other vulnerabilities in 9001 copyparty

- [CVE-2023-41471](https://insights.sbomify.com/CVE-2023-41471/): Cross-site scripting in n/a (high 7.8)
- [CVE-2025-54796](https://insights.sbomify.com/CVE-2025-54796/): Copyparty is vulnerable to Regex Denial of Service (ReDoS) attacks through "Recent Uploads" page (high 7.5)
- [CVE-2023-37474](https://insights.sbomify.com/CVE-2023-37474/): Path traversal in copyparty (high 7.5)
- [CVE-2025-54589](https://insights.sbomify.com/CVE-2025-54589/): copyparty Reflected XSS via Filter Parameter (medium 6.3)
- [CVE-2023-38501](https://insights.sbomify.com/CVE-2023-38501/): copyparty vulnerable to reflected cross-site scripting via k304 parameter (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-30974 and fix it if it is affected.

What it is: CVE-2026-30974 is a medium-severity cross-site scripting vulnerability in 9001 copyparty, published on 10 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-30974 in the wild and no public exploit code.

Affected packages and fixed versions:
- copyparty (PyPI): affected all versions; fixed in 1.20.11
- copyparty (PyPI): affected all versions; fixed in 1.20.11
- copyparty (PyPI): affected all versions; fixed in 1.20.11

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-2026-30974/ (Markdown: https://insights.sbomify.com/CVE-2026-30974/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-30974
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-30974
- OSV: https://osv.dev/vulnerability/CVE-2026-30974

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-30974/
Summaries are generated and may contain mistakes; the official description above is the record.