CVE-2011-1521

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

Severity Score

7.4

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The urllib and urllib2 modules in Python 2.x before 2.7.2 and 3.x before 3.2.1 process Location headers that specify redirection to file: URLs, which makes it easier for remote attackers to obtain sensitive information or cause a denial of service (resource consumption) via a crafted URL, as demonstrated by the file:///etc/passwd and file:///dev/zero URLs.

Los módulos urllib y urllib2 en Python v2.x anteriores a v2.7.2 y v3.x anteriores a v3.2.1 procesan los encabezados de ubicación que especificar la redirección del fichero: URLs, lo que hace que sea más fácil para los atacantes remotos obtener información sensible o provocar una denegación de servicio (consumo de recursos) a través de una URL manipulada, como lo demuestra lso ficheros URLs: //etc/passwd y //dev/zero.

The is_cgi method in CGIHTTPServer.py in the CGIHTTPServer module in Python 2.5, 2.6, and 3.0 allows remote attackers to read script source code via an HTTP GET request that lacks a / character at the beginning of the URI. A flaw was found in the Python urllib and urllib2 libraries where they would not differentiate between different target URLs when handling automatic redirects. This caused Python applications using these modules to follow any new URL that they understood, including the file:// URL type. This could allow a remote server to force a local Python application to read a local file instead of the remote one, possibly exposing local files that were not meant to be exposed.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2011-03-28 CVE Reserved
2011-05-22 CVE Published
2024-08-06 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-399: Resource Management Errors

CAPEC

References (27)

URL	Tag	Source
http://hg.python.org/cpython/file/96a6c128822b/Misc/NEWS	X_refsource_confirm
http://hg.python.org/cpython/file/b2934d98dac1/Misc/NEWS	X_refsource_confirm
http://openwall.com/lists/oss-security/2011/03/24/5	Mailing List
http://openwall.com/lists/oss-security/2011/03/28/2	Mailing List
http://openwall.com/lists/oss-security/2011/09/11/1	Mailing List
http://openwall.com/lists/oss-security/2011/09/13/2	Mailing List
http://openwall.com/lists/oss-security/2011/09/15/5	Mailing List
http://secunia.com/advisories/50858	Third Party Advisory
http://secunia.com/advisories/51024	Third Party Advisory
http://secunia.com/advisories/51040	Third Party Advisory
http://securitytracker.com/id?1025488	Vdb Entry
http://support.apple.com/kb/HT5002	X_refsource_confirm
https://bugzilla.redhat.com/show_bug.cgi?id=737366	X_refsource_confirm
https://www.djangoproject.com/weblog/2011/sep/09	X_refsource_confirm
https://www.djangoproject.com/weblog/2011/sep/10/127	X_refsource_confirm

URL	Date	SRC

URL	Date	SRC
http://bugs.python.org/issue11662	2019-10-25
http://hg.python.org/cpython/rev/96a6c128822b	2019-10-25
http://hg.python.org/cpython/rev/b2934d98dac1	2019-10-25
https://bugzilla.redhat.com/show_bug.cgi?id=690560	2011-05-19

URL	Date	SRC
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html	2019-10-25
http://lists.opensuse.org/opensuse-security-announce/2011-05/msg00005.html	2019-10-25
http://www.mandriva.com/security/advisories?name=MDVSA-2011:096	2019-10-25
http://www.ubuntu.com/usn/USN-1592-1	2019-10-25
http://www.ubuntu.com/usn/USN-1596-1	2019-10-25
http://www.ubuntu.com/usn/USN-1613-1	2019-10-25
http://www.ubuntu.com/usn/USN-1613-2	2019-10-25
https://access.redhat.com/security/cve/CVE-2011-1521	2011-05-19

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.0 Search vendor "Python" for product "Python" and version "2.0"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.0.1 Search vendor "Python" for product "Python" and version "2.0.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.1 Search vendor "Python" for product "Python" and version "2.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.1.1 Search vendor "Python" for product "Python" and version "2.1.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.1.2 Search vendor "Python" for product "Python" and version "2.1.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.1.3 Search vendor "Python" for product "Python" and version "2.1.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.2 Search vendor "Python" for product "Python" and version "2.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.2.1 Search vendor "Python" for product "Python" and version "2.2.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.2.2 Search vendor "Python" for product "Python" and version "2.2.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.2.3 Search vendor "Python" for product "Python" and version "2.2.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.1 Search vendor "Python" for product "Python" and version "2.3.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.2 Search vendor "Python" for product "Python" and version "2.3.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.3 Search vendor "Python" for product "Python" and version "2.3.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.4 Search vendor "Python" for product "Python" and version "2.3.4"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.5 Search vendor "Python" for product "Python" and version "2.3.5"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.3.7 Search vendor "Python" for product "Python" and version "2.3.7"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.4.1 Search vendor "Python" for product "Python" and version "2.4.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.4.2 Search vendor "Python" for product "Python" and version "2.4.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.4.3 Search vendor "Python" for product "Python" and version "2.4.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.4.4 Search vendor "Python" for product "Python" and version "2.4.4"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.4.6 Search vendor "Python" for product "Python" and version "2.4.6"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.5.1 Search vendor "Python" for product "Python" and version "2.5.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.5.2 Search vendor "Python" for product "Python" and version "2.5.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.5.3 Search vendor "Python" for product "Python" and version "2.5.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.5.4 Search vendor "Python" for product "Python" and version "2.5.4"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.6.1 Search vendor "Python" for product "Python" and version "2.6.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.6.4 Search vendor "Python" for product "Python" and version "2.6.4"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.6.5 Search vendor "Python" for product "Python" and version "2.6.5"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.6.6 Search vendor "Python" for product "Python" and version "2.6.6"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.6.7 Search vendor "Python" for product "Python" and version "2.6.7"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				2.7.1 Search vendor "Python" for product "Python" and version "2.7.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.0 Search vendor "Python" for product "Python" and version "3.0"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.0.1 Search vendor "Python" for product "Python" and version "3.0.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.1 Search vendor "Python" for product "Python" and version "3.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.1.1 Search vendor "Python" for product "Python" and version "3.1.1"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.1.2 Search vendor "Python" for product "Python" and version "3.1.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.1.3 Search vendor "Python" for product "Python" and version "3.1.3"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.2 Search vendor "Python" for product "Python" and version "3.2"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.2 Search vendor "Python" for product "Python" and version "3.2"		alpha		Affected