# PSF-2018-7: xml package does not obey ignore_environment

> The Python xml package ignores isolation flags, allowing environment variables to override parser implementations, bypassing security restrictions.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2018

## What is PSF-2018-7?

PSF-2018-7 is a vulnerability, published on 24 Sep 2018. 

### Official description

On two occasions, the xml package uses environment variables to override
parser / DOM implementations: ``xml.sax package`` and ``xml.dom.domreg``
module. On both occasions, the code should not use env vars to override
module names, when the interpreter is started with flags like ``-E``
or ``-I``.

## Which versions are affected by PSF-2018-7?


## How do I fix PSF-2018-7?

No fix has been published for PSF-2018-7 yet. Limit exposure of the affected software until one is available.

## Is PSF-2018-7 being exploited?

There is no known exploitation of PSF-2018-7 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for PSF-2018-7 and fix it if it is affected.

What it is: PSF-2018-7 is a vulnerability, published on 24 Sep 2018. 
Exploitation: There is no known exploitation of PSF-2018-7 in the wild and no public exploit code.

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/PSF-2018-7/ (Markdown: https://insights.sbomify.com/PSF-2018-7/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/PSF-2018-7

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From sbomify Insights: https://insights.sbomify.com/PSF-2018-7/
Summaries are generated and may contain mistakes; the official description above is the record.