# CVE-2021-32674: Remote Code Execution via traversal in TAL expressions

> Attackers with Manager role can execute arbitrary code via TAL expression traversal in Zope Page Templates, requiring restricted template editing permissions.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-5vq5-pg3r-9ph3, GHSA-rpcg-f9q6-2mq6, PYSEC-2021-104

## What is CVE-2021-32674?

CVE-2021-32674 is a high-severity code injection vulnerability in zopefoundation Zope, published on 8 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Zope is an open-source web application server. This advisory extends the previous advisory at https://github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36 with additional cases of TAL expression traversal vulnerabilities. Most Python modules are not available for using in TAL expressions that you can add through-the-web, for example in Zope Page Templates. This restriction avoids file system access, for example via the 'os' module. But some of the untrusted modules are available indirectly through Python modules that are available for direct use. By default, you need to have the Manager role to add or edit Zope Page Templates through the web. Only sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk. The problem has been fixed in Zope 5.2.1 and 4.6.1. The workaround is the same as for https://github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36: A site administrator can restrict adding/editing Zope Page Templates through the web using the standard Zope user/role permission mechanisms. Untrusted users should not be assigned the Zope Manager role and adding/editing Zope Page Templates through the web should be restricted to trusted users only.

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

## Which versions are affected by CVE-2021-32674?

9 open source packages ship an affected version, including zope and Zope. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `zope` | PyPI | All versions | 4.6.1 |
| `zope` | PyPI | All versions | 4.6.1 |
| `zope` | PyPI | From 4.0 | 4.6.1, 5.2.1 |
| `zope` | PyPI | From 5.0 | 5.2.1 |
| `zope` | PyPI | From 5.0 | 5.2.1 |
| `Zope` | PyPI | All versions | 4.6.1 |
| `Zope` | PyPI | All versions | 4.6.1 |
| `Zope` | PyPI | From 5.0 | 5.2.1 |
| `Zope` | PyPI | From 5.0 | 5.2.1 |

Products: Zope Zope.

## How do I fix CVE-2021-32674?

Upgrade zope to a fixed version for your release line: 4.6.1 or 5.2.1.

## Is CVE-2021-32674 being exploited?

There is no known exploitation of CVE-2021-32674 in the wild and no public exploit code.

## Other vulnerabilities in zopefoundation Zope

- [CVE-2000-0062](https://insights.sbomify.com/CVE-2000-0062/): Zope DTML implementation Improper Authentication (critical 10.0)
- [CVE-2000-1211](https://insights.sbomify.com/CVE-2000-1211/): Zope does not properly perform security registration for legacy names (high 7.5)
- [CVE-2002-0170](https://insights.sbomify.com/CVE-2002-0170/): Zope does not properly verify the access for objects with proxy roles (high 7.5)
- [CVE-2002-0688](https://insights.sbomify.com/CVE-2002-0688/): ZCatalog plug-in for Zope allows anonymous users to bypass access restrictions (high 7.5)
- [CVE-2001-1227](https://insights.sbomify.com/CVE-2001-1227/): Security feature bypass in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32674 and fix it if it is affected.

What it is: CVE-2021-32674 is a high-severity code injection vulnerability in zopefoundation Zope, published on 8 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-32674 in the wild and no public exploit code.

Affected packages and fixed versions:
- zope (PyPI): affected all versions; fixed in 4.6.1
- zope (PyPI): affected all versions; fixed in 4.6.1
- zope (PyPI): affected from 4.0; fixed in 4.6.1, 5.2.1
- zope (PyPI): affected from 5.0; fixed in 5.2.1
- zope (PyPI): affected from 5.0; fixed in 5.2.1
- Zope (PyPI): affected all versions; fixed in 4.6.1
- Zope (PyPI): affected all versions; fixed in 4.6.1
- Zope (PyPI): affected from 5.0; fixed in 5.2.1
- Zope (PyPI): affected from 5.0; fixed in 5.2.1

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-2021-32674/ (Markdown: https://insights.sbomify.com/CVE-2021-32674/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32674
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32674
- OSV: https://osv.dev/vulnerability/CVE-2021-32674

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-32674/
Summaries are generated and may contain mistakes; the official description above is the record.