How severe is CVE-2011-4940?

CVE-2011-4940 has a CVSS 2.0 base score of 2.6, rated low severity.

Is CVE-2011-4940 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-4940?

CVE-2011-4940 primarily affects Python. In total, 39 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-4940?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2011-4940 published?

CVE-2011-4940 was published on 2012-06-27 and last updated on 2026-06-16.

CVE-2011-4940

CVE-2011-4940 is a low-severity vulnerability in Python with a CVSS 2.0 base score of 2.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Low (CVSS 2.0 base score 2.6)
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Python
Published: 2012-06-27
Last modified: 2026-06-16

Description

The list_directory function in Lib/SimpleHTTPServer.py in SimpleHTTPServer in Python before 2.5.6c1, 2.6.x before 2.6.7 rc2, and 2.7.x before 2.7.2 does not place a charset parameter in the Content-Type HTTP header, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks against Internet Explorer 7 via UTF-7 encoding.

Frequently asked questions

What is CVE-2011-4940?: The list_directory function in Lib/SimpleHTTPServer.py in SimpleHTTPServer in Python before 2.5.6c1, 2.6.x before 2.6.7 rc2, and 2.7.x before 2.7.2 does not place a charset parameter in the Content-Type HTTP header, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks against Internet Explorer 7 via UTF-7 encoding.
How severe is CVE-2011-4940?: CVE-2011-4940 has a CVSS 2.0 base score of 2.6, rated low severity.
Is CVE-2011-4940 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-4940?: CVE-2011-4940 primarily affects Python. In total, 39 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-4940?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-4940 published?: CVE-2011-4940 was published on 2012-06-27 and last updated on 2026-06-16.

References

Affected products (39)

cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:0.9.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:0.9.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:1.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:1.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:1.5.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:1.6:*:*:*:*:*:*:*
cpe:2.3:a:python:python:1.6.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.0.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.1.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.1.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.1.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.2.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.2.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.2.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.5:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.3.7:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.4.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.4.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.4.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.4.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.4.6:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.5.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.5.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.5.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.5.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.5:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.6.6:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.7.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:2.7.1:rc1:*:*:*:*:*:*
cpe:2.3:a:python:python:2.7.2:rc1:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

121.164.135.251 (ipv4-addr)