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Servers and applications

CVE-2011-1521

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.

Severity
Medium 6.4
Published
24 May 2011
Last changed
16 Jun 2026
Added to UpHeron
21 Oct 2026
Exploit chance
3.6% in the next 30 daysHigher than 89% of CVEs. EPSS by FIRST, 12 Nov 2026
Weakness
CWE-399
Attack
Over the network · No login needed
Attacker can
Read some data · Slow it down
CVSS vector
AV:N/AC:L/Au:N/C:P/I:N/A:P
Sources
NVD

Affected software

SoftwareAffected versions
PythonServers and applications · cpe:a:python:python
  • Version 3.2
  • Version 3.2-alpha
  • Version 3.1.3
  • Version 3.1.2
All 39 release lines
  • Version 2.0
  • Version 2.0.1
  • Version 2.1
  • Version 2.1.1
  • Version 2.1.2
  • Version 2.1.3
  • Version 2.2
  • Version 2.2.1
  • Version 2.2.2
  • Version 2.2.3
  • Version 2.3.1
  • Version 2.3.2
  • Version 2.3.3
  • Version 2.3.4
  • Version 2.3.5
  • Version 2.3.7
  • Version 2.4.1
  • Version 2.4.2
  • Version 2.4.3
  • Version 2.4.4
  • Version 2.4.6
  • Version 2.5.1
  • Version 2.5.2
  • Version 2.5.3
  • Version 2.5.4
  • Version 2.6.1
  • Version 2.6.4
  • Version 2.6.5
  • Version 2.6.6
  • Version 2.6.7
  • Version 2.7.1
  • Version 3.0
  • Version 3.0.1
  • Version 3.1
  • Version 3.1.1
  • Version 3.1.2
  • Version 3.1.3
  • Version 3.2-alpha
  • Version 3.2

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2011-1521
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2011-1521