CVE-2018-20852: Input Validation
First published: Wed Oct 31 2018(Updated: )
Python could allow a remote attacker to obtain sensitive information, caused by the failure to correctly validate the domain by http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py. By using a server with a hostname that has another valid hostname as a suffix, an attacker could exploit this vulnerability to obtain leaked existing cookies.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/python | <0:2.7.5-88.el7 | 0:2.7.5-88.el7 |
| redhat/python3 | <0:3.6.8-13.el7 | 0:3.6.8-13.el7 |
| redhat/python3 | <0:3.6.8-23.el8 | 0:3.6.8-23.el8 |
| redhat/rh-python36-python | <0:3.6.9-2.el6 | 0:3.6.9-2.el6 |
| redhat/python27-python | <0:2.7.17-2.el6 | 0:2.7.17-2.el6 |
| redhat/rh-python36-python | <0:3.6.9-2.el7 | 0:3.6.9-2.el7 |
| redhat/python27-python | <0:2.7.17-2.el7 | 0:2.7.17-2.el7 |
| Python Python | >=2.0<=2.7.16 | |
| Python Python | >=3.0.0<3.4.10 | |
| Python Python | >=3.5.0<3.5.7 | |
| Python Python | >=3.6.0<3.6.9 | |
| Python Python | >=3.7.0<3.7.3 | |
| IBM ISAM | <=9.0.7 | |
| IBM Security Verify Access | <=10.0.0 | |
| ubuntu/python2.7 | <2.7.15-4ubuntu4~18.04.1 | 2.7.15-4ubuntu4~18.04.1 |
| ubuntu/python2.7 | <2.7.16-2ubuntu0.1 | 2.7.16-2ubuntu0.1 |
| ubuntu/python2.7 | <2.7.6-8ubuntu0.6+ | 2.7.6-8ubuntu0.6+ |
| ubuntu/python2.7 | <2.7.16-3 | 2.7.16-3 |
| ubuntu/python2.7 | <2.7.12-1ubuntu0~16.04.8 | 2.7.12-1ubuntu0~16.04.8 |
| ubuntu/python3.4 | <3.4.3-1ubuntu1~14.04.7+ | 3.4.3-1ubuntu1~14.04.7+ |
| ubuntu/python3.4 | <3.4.10 | 3.4.10 |
| ubuntu/python3.5 | <3.5.7 | 3.5.7 |
| ubuntu/python3.5 | <3.5.2-2ubuntu0~16.04.8 | 3.5.2-2ubuntu0~16.04.8 |
| ubuntu/python3.6 | <3.6.8-1~18.04.2 | 3.6.8-1~18.04.2 |
| ubuntu/python3.6 | <3.6.9 | 3.6.9 |
| ubuntu/python3.7 | <3.7.3~ | 3.7.3~ |
| redhat/Python | <3.4.10 | 3.4.10 |
| redhat/Python | <3.5.7 | 3.5.7 |
| redhat/Python | <3.6.9 | 3.6.9 |
| redhat/Python | <3.7.3 | 3.7.3 |
| debian/python2.7 | 2.7.16-2+deb10u1 2.7.16-2+deb10u4 2.7.18-8+deb11u1 | |
| debian/python3.7 | 3.7.3-2+deb10u3 3.7.3-2+deb10u7 |
Remedy
A potentially simple workaround in the absence of patch on affected versions is to set DomainStrict in the cookiepolicy that would make sure a literal match against domain. The disadvantage would be that cookie set on example.com would not be shared with subdomain which might break workflow.
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Reference Links
- https://www.cve.org/CVERecord?id=CVE-2018-20852 https://nvd.nist.gov/vuln/detail/CVE-2018-20852
- https://bugzilla.redhat.com/show_bug.cgi?id=1740347
- https://access.redhat.com/errata/RHBA-2020:1539
- https://access.redhat.com/errata/RHBA-2020:1540
- https://access.redhat.com/errata/RHSA-2020:1131
- https://access.redhat.com/errata/RHSA-2020:1132
- https://access.redhat.com/errata/RHSA-2020:1605
- https://access.redhat.com/errata/RHSA-2020:1764
- https://access.redhat.com/errata/RHSA-2019:3725
- https://access.redhat.com/errata/RHSA-2019:3948
- https://access.redhat.com/security/cve/cve-2018-20852
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00071.html
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00074.html
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
- https://bugs.python.org/issue35121
- https://lists.debian.org/debian-lts-announce/2019/08/msg00022.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00040.html
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/
- https://python-security.readthedocs.io/vuln/cookie-domain-check.html
- https://security.gentoo.org/glsa/202003-26
- https://usn.ubuntu.com/4127-1/
- https://usn.ubuntu.com/4127-2/
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://launchpad.net/bugs/cve/CVE-2018-20852
- https://exchange.xforce.ibmcloud.com/vulnerabilities/169515
- https://www.ibm.com/support/pages/node/6348046 (Advisory)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740348
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740349
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740351
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740356
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740353
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740352
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740358
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740354
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1740355
- https://access.redhat.com/support/policy/updates/errata/
- https://github.com/python/cpython/commit/979daae300916adb399ab5b51410b6ebd0888f13
- https://github.com/python/cpython/commit/42ad4101d3ba7ca3c371dadf0f8880764c9f15fb
- https://github.com/python/cpython/commit/4749f1b69000259e23b4cc6f63c542a9bdc62f1b
- https://github.com/python/cpython/commit/b241af861b37e20ad30533bc0b7e2e5491cc470f
- https://github.com/python/cpython/commit/e5123d81ffb3be35a1b2767d6ced1a097aaf77be
- https://security-tracker.debian.org/tracker/CVE-2018-20852
- https://ubuntu.com/security/notices/USN-4127-1
- https://ubuntu.com/security/notices/USN-4127-2
- https://www.cve.org/CVERecord?id=CVE-2018-20852
- https://nvd.nist.gov/vuln/detail/CVE-2018-20852
- https://ubuntu.com/security/CVE-2018-20852
Parent vulnerabilities
(Appears in the following advisories)
Frequently Asked Questions
What is CVE-2018-20852?
CVE-2018-20852 is a vulnerability in Python before version 3.7.3 that allows an attacker to trick the cookiejar into sending existing cookies to the wrong server.
How severe is CVE-2018-20852?
CVE-2018-20852 has a severity rating of 5.3 (Medium).
Which versions of Python are affected by CVE-2018-20852?
Python versions before 3.7.3 are affected by CVE-2018-20852.
How can I fix CVE-2018-20852?
To fix CVE-2018-20852, upgrade your Python version to 3.7.3 or later.
Where can I find more information about CVE-2018-20852?
You can find more information about CVE-2018-20852 at the following references: [1] [2] [3].
- collector/redhat-cve
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- collector/launchpad-cve
- source/Launchpad
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- agent/software-canonical-lookup-request
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- version/python python/3.7.0
- vendor/ibm
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