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CVE-2011-1521

24
FAUCET Score

CVE-2011-1521 describes a vulnerability in the urllib and urllib2 modules of Python 2.x (before 2.7.2) and 3.x (before 3.2.1) where redirection to "file:" URLs in Location headers is improperly handled. This flaw allows remote attackers to access sensitive local files, such as /etc/passwd, or trigger a denial of service by requesting large files like /dev/zero. With a CVSS score of 6.4, this vulnerability is of medium severity, indicating it can be exploited remotely with low attack complexity to achieve partial confidentiality and availability impacts. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
2.0CPE matchmatch criteria
cpe:2.3:a:python:python:2.0:*:*:*:*:*:*:*
2.0.1CPE matchmatch criteria
cpe:2.3:a:python:python:2.0.1:*:*:*:*:*:*:*
2.1CPE matchmatch criteria
cpe:2.3:a:python:python:2.1:*:*:*:*:*:*:*
2.1.1CPE matchmatch criteria
cpe:2.3:a:python:python:2.1.1:*:*:*:*:*:*:*
2.1.2CPE matchmatch criteria
cpe:2.3:a:python:python:2.1.2:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

6.4MEDIUM

AV:N/AC:L/Au:N/C:P/I:N/A:P

Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
4.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
4.10%
Probability of exploitation in next 30 days
EPSS Percentile
89.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0410 is in the 86th percentile among its peer group of 23,723 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 4Fixed in: python-0:2.3.4-14.10.el4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: python-0:2.4.3-44.el5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: python-0:2.6.6-20.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: python-docs-0:2.6.6-2.el6
View patch

Vendor Advisories (1)

redhatCVE-2011-1521Moderate

urllib2): Improper management of ftp:// and file:// URL schemes (Issue #11662)

Mar 24, 2011

References

bugs.python.org / issue11662
Patch
hg.python.org / cpython/file/96a6c128822b/Misc/NEWS
hg.python.org / cpython/file/b2934d98dac1/Misc/NEWS
hg.python.org / cpython/rev/96a6c128822b
Patch
hg.python.org / cpython/rev/b2934d98dac1
Patch
lists.apple.com / archives/Security-announce/2011//Oct/msg00003.html
lists.opensuse.org / opensuse-security-announce/2011-05/msg00005.html
openwall.com / lists/oss-security/2011/03/24/5
openwall.com / lists/oss-security/2011/03/28/2
openwall.com / lists/oss-security/2011/09/11/1
openwall.com / lists/oss-security/2011/09/13/2
openwall.com / lists/oss-security/2011/09/15/5
bugzilla.redhat.com / show_bug.cgi
Patch
bugzilla.redhat.com / show_bug.cgi
secunia.com / advisories/50858
secunia.com / advisories/51024
secunia.com / advisories/51040
securitytracker.com / id
support.apple.com / kb/HT5002
djangoproject.com / weblog/2011/sep/09
djangoproject.com / weblog/2011/sep/10/127
mandriva.com / security/advisories
ubuntu.com / usn/USN-1592-1
ubuntu.com / usn/USN-1596-1
ubuntu.com / usn/USN-1613-1
ubuntu.com / usn/USN-1613-2