CVE-2021-33511

HIGHNVD 7.57.5—

7.5

Plone though 5.2.4 allows SSRF via the lxml parser. This affects Diazo themes, Dexterity TTW schemas, and modeleditors in plone.app.theming, plone.app.dexterity, and plone.supermodel.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 51.2%
KEV: Not listed

Published

May 21, 2021

Last Modified

November 21, 2024

References (4)

cve@mitrehttp://www.openwall.com/lists/oss-security/2021/05/22/1
cve@mitrehttps://plone.org/security/hotfix/20210518/server-side-request-forgery-via-lxml-parser
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/05/22/1
af854a3a-2127-422b-91ae-364da2661108https://plone.org/security/hotfix/20210518/server-side-request-forgery-via-lxml-parser

Patch Availability(1)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
pip	Plone	—	ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)

PyPI(1)

Package	Vulnerable range	Fixed in	Dependents
plone	3.2 ... 5.2rc5 (145 versions)	5.2.5	—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-918Server-Side Request Forgery (SSRF)

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 16:16 UTCEG score recompute
2026-05-26 16:16 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-33511?

CVE-2021-33511 is a high vulnerability published on May 21, 2021. Plone though 5.2.4 allows SSRF via the lxml parser. This affects Diazo themes, Dexterity TTW schemas, and modeleditors in plone.app.theming, plone.app.dexterity, and plone.supermodel.

When was CVE-2021-33511 disclosed?

CVE-2021-33511 was first published in the National Vulnerability Database on May 21, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-33511 actively exploited?

CVE-2021-33511 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 51.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-33511?

CVE-2021-33511 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2021-33511?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-33511, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-33511

Published

Last Modified

References (4)

Patch Availability(1)

Affected Packages

Weakness Classification(1)

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-33511?

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CVE-2021-33511

📅 Published

🔄 Last Modified

🔗 References (4)

Patch Availability(1)

Affected Packages

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-33511?

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