CVE-2021-32633
Remote Code Execution via traversal in TAL expressions
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.8
Remote Code Execution via traversal in TAL expressions
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
CVE-2021-32633- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
EUVDEUVD-2021-0471
6.8
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
EUVD-2021-0471- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-5pr9-v234-jw36
7.6
Remote Code Execution via traversal in TAL expressions
Impact
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.
Patches
The problem has been fixed in Zope 5.2 and 4.6.
Workarounds
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.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Zope issue tracker
- Email us at [email protected]
- Record
GHSA-5pr9-v234-jw36- CVSS 4.0
- 7.6 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
GitHub AdvisoriesGHSA-962m-m8jw-8wrr
8.8
Duplicate Advisory: Path Traversal in Zope
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-5pr9-v234-jw36. This link is maintained to preserve external references.
Original Description
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
GHSA-962m-m8jw-8wrr- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-22
- Updated
- 2026-11-02
NVD
6.8
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
CVE-2021-32633- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-22
- Updated
- 2026-11-02
OSV
8.8
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
CVE-2021-32633- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-5pr9-v234-jw36
7.6
Remote Code Execution via traversal in TAL expressions
Impact
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.
Patches
The problem has been fixed in Zope 5.2 and 4.6.
Workarounds
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.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the Zope issue tracker
- Email us at [email protected]
- Record
GHSA-5pr9-v234-jw36- CVSS 4.0
- 7.6 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-22
- Updated
- 2026-11-02
OSVGHSA-962m-m8jw-8wrr
8.8
Duplicate Advisory: Path Traversal in Zope
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-5pr9-v234-jw36. This link is maintained to preserve external references.
Original Description
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
GHSA-962m-m8jw-8wrr- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-22
- Updated
- 2026-11-02
OSVPYSEC-2021-88 No score
Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, 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.
- Record
PYSEC-2021-88- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
zopePyPI |
before 4.6 | 4.6 |
zopePyPI |
5.0 up to 5.2 | 5.2 |
zopePyPI |
before 4.6, plus listed versions 4.04.0b14.0b104.0b24.0b3 Show 24 moreShow less4.0b44.0b54.0b64.0b74.0b84.0b94.14.1.14.1.24.1.34.24.2.14.34.44.4.14.4.24.4.34.4.44.54.5.14.5.24.5.34.5.44.5.5 |
4.6 |
zopePyPI |
5.0 up to 5.2, plus listed versions 5.15.1.15.1.2 |
5.2 |
zopePyPI |
before 4.6, 5.0 up to 5.2, plus listed versions 4.04.0b14.0b104.0b24.0b3 Show 27 moreShow less4.0b44.0b54.0b64.0b74.0b84.0b94.14.1.14.1.24.1.34.24.2.14.34.44.4.14.4.24.4.34.4.44.54.5.14.5.24.5.34.5.44.5.55.15.1.15.1.2 |
4.65.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32633 is a medium vulnerability (CVSS 6.8) in Zope, published May 21, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.86%, the 79th percentile. Fixed in zope 4.6.
References
github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36
github.com/zopefoundation/Zope/commit/1f8456bf1f908ea46012537d52bd7e752a532c91
openwall.com/lists/oss-security/2021/05/21/1
openwall.com/lists/oss-security/2021/05/22/1
cyllective.com/blog/post/plone-authenticated-rce-cve-2021-32633
nvd.nist.gov/vuln/detail/CVE-2021-32633