# CVE-2023-40587: Pyramid static view path traversal up one directory

> Attackers can read index.html files one directory above static views in Pyramid when using specific Python versions and configurations.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Aug 2023
- **Updated:** 13 Feb 2025
- **Also known as:** DEBIAN-CVE-2023-40587, GHSA-j8g2-6fc7-q8f8, PYSEC-2026-1840, UBUNTU-CVE-2023-40587

## What is CVE-2023-40587?

CVE-2023-40587 is a medium-severity path traversal vulnerability in Fedoraproject Fedora, published on 25 Aug 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Pyramid is an open source Python web framework. A path traversal vulnerability in Pyramid versions 2.0.0 and 2.0.1 impacts users of Python 3.11 that are using a Pyramid static view with a full filesystem path and have a `index.html` file that is located exactly one directory above the location of the static view's file system path. No further path traversal exists, and the only file that could be disclosed accidentally is `index.html`. Pyramid version 2.0.2 rejects any path that contains a null-byte out of caution. While valid in directory/file names, we would strongly consider it a mistake to use null-bytes in naming files/directories. Secondly, Python 3.11, and 3.12 has fixed the underlying issue in `os.path.normpath` to no longer truncate on the first `0x00` found, returning the behavior to pre-3.11 Python, un an as of yet unreleased version. Fixes will be available in:Python 3.12.0rc2 and 3.11.5. Some workarounds are available. Use a version of Python 3 that is not affected, downgrade to Python 3.10 series temporarily, or wait until Python 3.11.5 is released and upgrade to the latest version of Python 3.11 series.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2023-40587?

3 open source packages ship an affected version, including pyramid. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pyramid` | PyPI | From 2.0.0 | 2.0.2 |
| `pyramid` | PyPI | From 2.0.0 | 2.0.2 |
| `pyramid` | PyPI | From 2.0.0 | 2.0.2 |

Products: Agendaless Pyramid, Fedoraproject Fedora.

## How do I fix CVE-2023-40587?

Upgrade pyramid to 2.0.2 or later.

## Is CVE-2023-40587 being exploited?

There is no known exploitation of CVE-2023-40587 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-40587 and fix it if it is affected.

What it is: CVE-2023-40587 is a medium-severity path traversal vulnerability in Fedoraproject Fedora, published on 25 Aug 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-40587 in the wild and no public exploit code.

Affected packages and fixed versions:
- pyramid (PyPI): affected from 2.0.0; fixed in 2.0.2
- pyramid (PyPI): affected from 2.0.0; fixed in 2.0.2
- pyramid (PyPI): affected from 2.0.0; fixed in 2.0.2

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-2023-40587/ (Markdown: https://insights.sbomify.com/CVE-2023-40587/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-40587
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-40587
- OSV: https://osv.dev/vulnerability/CVE-2023-40587

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-40587/
Summaries are generated and may contain mistakes; the official description above is the record.