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

Exp

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.

Published: 2021-05-21 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2021-32633

EPSS CVSS CWE GHSA Exploit-DB Affected

Conclusion & alert: CVE-2021-32633 is rated High Exploit Risk (68.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.94%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-32633

EDB-ID	Source	Kind	Published	Link
—	nvd_ref	exploit_tag		Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-32633

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-04-20	0.52%	0.94%	+0.42%
2	2025-03-30	1.09%	0.52%	-0.57%
3	2025-03-29	—	1.09%	—

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-32633

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.8	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	1.6	5.2	[email protected]
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]
6.5	2.0	MEDIUM	`AV:N/AC:L/Au:S/C:P/I:P/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:S) A single authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	8.0	6.4	[email protected]

Weakness enumeration for CVE-2021-32633

CWE-22 MITRE ↗

GitHub Security Advisory for CVE-2021-32633

GHSA-5pr9-v234-jw36 · Severity: high · Ecosystem: pip — Remote Code Execution via traversal in TAL expressions

Affected software / configurations for CVE-2021-32633

Vendor	Product	Version	Raw CPE
plone	plone	<= 4.3.20	cpe:2.3:a:plone:plone::::::::
plone	plone	>= 5.0, <= 5.2.4	cpe:2.3:a:plone:plone::::::::
zope	zope	< 4.6	cpe:2.3:a:zope:zope::::::::
zope	zope	>= 5.0, < 5.2	cpe:2.3:a:zope:zope::::::::

References for CVE-2021-32633

URL	Tags
http://www.openwall.com/lists/oss-security/2021/05/21/1	Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/22/1	Mailing List Third Party Advisory
https://cyllective.com/blog/post/plone-authenticated-rce-cve-2021-32633/	Exploit Third Party Advisory
https://github.com/zopefoundation/Zope/commit/1f8456bf1f908ea46012537d52bd7e752a532c91	Patch Third Party Advisory
https://github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36	Third Party Advisory

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