How severe is CVE-2011-1340?

No CVSS score has been assigned to CVE-2011-1340 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2011-1340?

CVE-2011-1340 affects the following packages: plone (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2011-1340?

Update plone to 2.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-1340 is resolved across your whole dependency graph.

How do I detect CVE-2011-1340 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plone, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2011-1340 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2011-1340 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2011-1340, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2011-1340?

CVE-2011-1340 has an EPSS (Exploit Prediction Scoring System) score of 1.2%, placing it in the 67th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2011-1340?

CVE-2011-1340 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2011-1340 published, and has it been updated?

CVE-2011-1340 was published on May 17, 2022 and was last updated on July 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2011-1340 — plone

CVE-2011-1340 is a Cross-site Scripting (XSS) vulnerability in plone. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for plone — see the affected versions and patch details below.

Plone XSS Vulnerability

Also known asPYSEC-2026-896

Published

May 17, 2022

Updated

Jul 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍plone

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Cross-site scripting (XSS) vulnerability in skins/plone_templates/default_error_message.pt in Plone before 2.5.3 allows remote attackers to inject arbitrary web script or HTML via the type_name parameter to Members/ipa/createObject.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`plone`	all versions	2.5.3`pip install --upgrade 'plone==2.5.3'`

Affected Products

1 product · 21 configurations

Application

ploneplone

≤ 2.5.2

20 versions

1.01.0.11.0.21.0.31.0.41.0.51.0.62.02.0.12.0.22.0.32.0.4

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Cross-site scripting (XSS) vulnerability in skins/plone_templates/defaul…

dev.plone.orgNVDAug 2011

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plone, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update plone to 2.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-1340 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

Cross-site scripting (XSS) vulnerability in `skins/plone_templates/default_error_message.pt` in Plone before 2.5.3 allows remote attackers to inject arbitrary web script or HTML via the type_name parameter to `Members/ipa/createObject`.

O3 Security · Impact-Aware SCA

Is CVE-2011-1340 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works