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Fencer Vulns
medium 6.1

CVE-2016-5699 json

CRLF injection vulnerability in the HTTPConnection.putheader function in urllib2 and urllib in CPython (aka Python) before 2.7.10 and 3.x b…

published 2016-09-02 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-6641

cvss
6.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
9.9%
EPSS 9.9% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

CRLF injection vulnerability in the HTTPConnection.putheader function in urllib2 and urllib in CPython (aka Python) before 2.7.10 and 3.x before 3.4.4 allows remote attackers to inject arbitrary HTTP headers via CRLF sequences in a URL.

Patch / fix

  • python2.7 Debian 11 2.7.10~rc1-1

debian advisories DEBIAN-CVE-2016-5699

  • python2.7 Ubuntu 14.04 LTS 2.7.6-8ubuntu0.3
  • python3.4 Ubuntu 14.04 LTS 3.4.3-1ubuntu1~14.04.5

ubuntu advisories UBUNTU-CVE-2016-5699

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rh-python34-python RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-14.el6
  • rh-python34-python RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-13.el7
  • rh-python34-python-libs RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-14.el6
  • rh-python34-python-libs RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-13.el7
  • rh-python34-python-test RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-14.el6
  • rh-python34-python-test RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-13.el7
  • rh-python34-python-tools RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-14.el6
  • rh-python34-python-tools RHEL 2 SOFTWARE_COLLECTIONS 3.4.2-13.el7

red hat advisories RHSA-2016:1630RHSA-2016:1629RHSA-2016:1628RHSA-2016:1627RHSA-2016:1626

  • python SLE Module for Python 2 15 SP1, SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 +2 more 2.7.17-7.32.2
  • python-base SLE Module for Python 2 15 SP1, SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 2.7.17-7.32.1
  • python3 SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 3.6.10-3.42.2
  • python3-base SLE Module for Development Tools 15 SP1, SLE Module for Development Tools 15, SLE Module for Basesystem 15 SP1 +1 more 3.6.10-3.42.2
  • python3 SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2, SLES 12 SP2 +1 more 3.4.5-19.1
  • python3-base SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2, SLES 12 SP2 +2 more 3.4.5-19.1
  • python3 SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 3.4.5-17.1
  • python3-base SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +2 more 3.4.5-17.1

suse advisories SUSE-SU-2020:0234-1SUSE-SU-2020:0114-1SUSE-SU-2019:0223-1SUSE-SU-2016:2859-1SUSE-SU-2016:2653-1SUSE-SU-2016:2270-1

  • python openSUSE Tumbleweed 2.7.12-1.5
  • python-base openSUSE Tumbleweed 2.7.12-1.4
  • python36 openSUSE Tumbleweed 3.6.15-1.1
  • python3 openSUSE Leap 15.1 3.6.10-lp151.6.7.1
  • python3-base openSUSE Leap 15.1 3.6.10-lp151.6.7.1

opensuse advisories openSUSE-SU-2024:10450-1openSUSE-SU-2024:10536-1openSUSE-SU-2024:11284-1openSUSE-SU-2020:0086-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-5699 updated cvss 5.3

python: http protocol steam injection attack

  • Red Hat Enterprise Linux 5 python
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) python 2.7.5-38.el7_2, python-libs 2.7.5-38.el7_2 Red Hat Enterprise Linux Client Optional (v. 7) tkinter 2.7.5-38.el7_2, python-test 2.7.5-38.el7_2, python-tools 2.7.5-38.el7_2 Red Hat Enterprise Linux ComputeNode (v. 7) python 2.7.5-38.el7_2, python-libs 2.7.5-38.el7_2 Red Hat Enterprise Linux ComputeNode Optional (v. 7) tkinter 2.7.5-38.el7_2, python-test 2.7.5-38.el7_2, python-tools 2.7.5-38.el7_2 Red Hat Enterprise Linux Desktop (v. 6) python 2.6.6-66.el6_8, tkinter 2.6.6-66.el6_8, python-libs 2.6.6-66.el6_8 Red Hat Enterprise Linux Desktop Optional (v. 6) python-test 2.6.6-66.el6_8, python-tools 2.6.6-66.el6_8
    +10 more products
    Red Hat Enterprise Linux HPC Node (v. 6) python 2.6.6-66.el6_8, python-libs 2.6.6-66.el6_8 Red Hat Enterprise Linux HPC Node Optional (v. 6) tkinter 2.6.6-66.el6_8, python-test 2.6.6-66.el6_8, python-tools 2.6.6-66.el6_8 Red Hat Enterprise Linux Server (v. 6) python 2.6.6-66.el6_8, tkinter 2.6.6-66.el6_8, python-libs 2.6.6-66.el6_8 Red Hat Enterprise Linux Server (v. 7) python 2.7.5-38.el7_2, python-libs 2.7.5-38.el7_2 Red Hat Enterprise Linux Server Optional (v. 6) tkinter 2.6.6-66.el6_8, python-test 2.6.6-66.el6_8, python-tools 2.6.6-66.el6_8 Red Hat Enterprise Linux Server Optional (v. 7) tkinter 2.7.5-38.el7_2, python-test 2.7.5-38.el7_2, python-tools 2.7.5-38.el7_2 Red Hat Enterprise Linux Workstation (v. 6) python 2.6.6-66.el6_8, tkinter 2.6.6-66.el6_8, python-libs 2.6.6-66.el6_8 Red Hat Enterprise Linux Workstation (v. 7) python 2.7.5-38.el7_2, python-libs 2.7.5-38.el7_2 Red Hat Enterprise Linux Workstation Optional (v. 6) python-test 2.6.6-66.el6_8, python-tools 2.6.6-66.el6_8 Red Hat Enterprise Linux Workstation Optional (v. 7) tkinter 2.7.5-38.el7_2, python-test 2.7.5-38.el7_2, python-tools 2.7.5-38.el7_2
    fixed: vendor fix RHSA-2016:1626
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) python27-python 2.7.8-18.el6, python33-python 3.3.2-18.el6, python27-tkinter 2.7.8-18.el6, rh-python34-python 3.4.2-14.el6, python27-python-libs 2.7.8-18.el6, python27-python-test 2.7.8-18.el6, +9 more Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) python27-python 2.7.8-16.el7, python33-python 3.3.2-16.el7, python27-tkinter 2.7.8-16.el7, rh-python35-python 3.5.1-9.el7, rh-python34-python 3.4.2-13.el7, python27-python-libs 2.7.8-16.el7, +14 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.6) python27-python 2.7.8-18.el6, python33-python 3.3.2-18.el6, python27-tkinter 2.7.8-18.el6, rh-python34-python 3.4.2-14.el6, python27-python-libs 2.7.8-18.el6, python27-python-test 2.7.8-18.el6, +9 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) python27-python 2.7.8-18.el6, python33-python 3.3.2-18.el6, python27-tkinter 2.7.8-18.el6, rh-python34-python 3.4.2-14.el6, python27-python-libs 2.7.8-18.el6, python27-python-test 2.7.8-18.el6, +9 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.1) python27-python 2.7.8-16.el7, python33-python 3.3.2-16.el7, python27-tkinter 2.7.8-16.el7, rh-python35-python 3.5.1-9.el7, rh-python34-python 3.4.2-13.el7, python27-python-libs 2.7.8-16.el7, +14 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.2) python27-python 2.7.8-16.el7, python33-python 3.3.2-16.el7, python27-tkinter 2.7.8-16.el7, rh-python35-python 3.5.1-9.el7, rh-python34-python 3.4.2-13.el7, python27-python-libs 2.7.8-16.el7, +14 more
    +2 more products
    Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) python27-python 2.7.8-18.el6, python33-python 3.3.2-18.el6, python27-tkinter 2.7.8-18.el6, rh-python34-python 3.4.2-14.el6, python27-python-libs 2.7.8-18.el6, python27-python-test 2.7.8-18.el6, +9 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) python27-python 2.7.8-16.el7, python33-python 3.3.2-16.el7, python27-tkinter 2.7.8-16.el7, rh-python35-python 3.5.1-9.el7, rh-python34-python 3.4.2-13.el7, python27-python-libs 2.7.8-16.el7, +14 more
    fixed: vendor fix RHSA-2016:1628

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

9.89% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • blog.blindspotsecurity.com http://blog.blindspotsecurity.com/2016/06/advisory-http-header-injection-in.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 6.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.