NVD / CVE Program· CNA GitHub_M

CVE-2021-32633: Remote Code Execution via traversal in TAL expressions

Noroxi assessment

Priority: Monitor (action score 36/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 1.8% (FIRST EPSS); higher than 79.2% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: zope (PyPI) 5.2, 4.6.
Severity is disputed: the assigning authority (CNA) scores it 6.8, NVD 8.8.

Low priority for now. Upgrade to zope (PyPI) 5.2, 4.6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 8.8 · v3.1—No exploit Fix available

Published: May 21, 2021
Updated: Jun 16, 2026
EPSS: 1.8% · 79th percentile
CWE: CWE-22

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 1 / 30 · 1.8%

CNA vs NVD score

NVD: 8.8
CNA · GitHub_M: 6.8; 2.0 point gap

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
zope	zope	cpe:2.3:a:zope:zope
plone	plone	cpe:2.3:a:plone:plone

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

plone ploneup to 4.3.20 inclusive
plone plone5.0 and later · up to 5.2.4 inclusive
zope zopebefore 4.6
zope zope5.0 and later · before 5.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

zopefoundation Zope
- < 4.6, >= 5.0, < 5.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
PyPI	zope	from 5.0 · before 5.2	5.2
PyPI	zope	before 4.6	4.6

Same product

zope: all records

Other highest-scoring records for the same primary product.

CVE-2000-0062The DTML implementation in the Z Object Publishing Environment (Zope) allows remote attackers to conduct unauthorized activities.
41Plan
CVE-2021-32674Remote Code Execution via traversal in TAL expressions
35Monitor
CVE-2005-3323docutils in Zope 2.6, 2.7 before 2.7.8, and 2.8 before 2.8.2 allows remote attackers to include arbitrary files via include directives in Re
31Monitor

Published before and after this one in the same product

← EarlierCVE-2009-5145Aug 7, 2017 · Cross-site scripting (XSS) vulnerability in ZMI pages that use the manage_tabs_message in Zope 2.11.4, 2.11.2, 2.10.9, 2.10.7, 2.10.6, 2.10.
25Monitor
← EarlierCVE-2011-4924Nov 25, 2019 · Cross-site scripting (XSS) vulnerability in Zope 2.8.x before 2.8.12, 2.9.x before 2.9.12, 2.10.x before 2.10.11, 2.11.x before 2.11.6, and
24Monitor
Later →CVE-2023-42458Sep 21, 2023 · Zope vulnerable to Stored Cross Site Scripting with SVG images
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
PyPI:zope	4.6	Package registry (OSV)
PyPI:zope	5.2	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

zopefoundation/Zopecommit 1f8456b

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

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References

www.openwall.com/lists/oss-security/2021/05/21/1

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records