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CVE-2018-20852· NVD / CVE Program· CNA mitre

http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can

Noroxi assessment

Priority: Monitor (action score 18/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 3.6% (FIRST EPSS); higher than 89.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: python-psycopg2-doc (AlmaLinux:8) 2.7.5-7.module_el8.6.0+2781+fed64c13; python2-attrs (AlmaLinux:8) 17.4.0-10.module_el8.6.0+2781+fed64c13; python2-chardet (AlmaLinux:8) 3.0.4-10.module_el8.6.0+2781+fed64c13.
  • Mentioned 4 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to python-psycopg2-doc (AlmaLinux:8) 2.7.5-7.module_el8.6.0+2781+fed64c13; python2-attrs (AlmaLinux:8) 17.4.0-10.module_el8.6.0+2781+fed64c13; python2-chardet (AlmaLinux:8) 3.0.4-10.module_el8.6.0+2781+fed64c13 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). When a program uses http.cookiejar.DefaultPolicy and tries to do an HTTP connection to an attacker-controlled server, existing cookies can be leaked to the attacker. This affects 2.x through 2.7.16, 3.x before 3.4.10, 3.5.x before 3.5.7, 3.6.x before 3.6.9, and 3.7.x before 3.7.3.

MediumCVSS 4.3 · v3.1—No exploit Fix available
Published
Jul 13, 2019
Updated
Oct 7, 2026
EPSS
3.7% · 89th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
pythonpython

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • python python2.0 and later · up to 2.7.16 inclusive
  • python python3.0.0 and later · before 3.4.10
  • python python3.5.0 and later · before 3.5.7
  • python python3.6.0 and later · before 3.6.9
  • python python3.7.0 and later · before 3.7.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8python-psycopg2-docbefore 2.7.5-7.module_el8.6.0+2781+fed64c132.7.5-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-attrsbefore 17.4.0-10.module_el8.6.0+2781+fed64c1317.4.0-10.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-chardetbefore 3.0.4-10.module_el8.6.0+2781+fed64c133.0.4-10.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-coveragebefore 4.5.1-4.module_el8.6.0+2781+fed64c134.5.1-4.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-Cythonbefore 0.28.1-7.module_el8.6.0+2781+fed64c130.28.1-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-dnsbefore 1.15.0-10.module_el8.6.0+2781+fed64c131.15.0-10.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-docsbefore 2.7.16-2.module_el8.6.0+2781+fed64c132.7.16-2.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-docs-infobefore 2.7.16-2.module_el8.6.0+2781+fed64c132.7.16-2.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-docutilsbefore 0.14-12.module_el8.6.0+2781+fed64c130.14-12.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-funcsigsbefore 1.0.2-13.module_el8.6.0+2781+fed64c131.0.2-13.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-idnabefore 2.5-7.module_el8.6.0+2781+fed64c132.5-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-ipaddressbefore 1.0.18-6.module_el8.6.0+2781+fed64c131.0.18-6.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-markupsafebefore 0.23-19.module_el8.6.0+2781+fed64c130.23-19.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-mockbefore 2.0.0-13.module_el8.6.0+2781+fed64c132.0.0-13.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pluggybefore 0.6.0-8.module_el8.6.0+2781+fed64c130.6.0-8.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-psycopg2before 2.7.5-7.module_el8.6.0+2781+fed64c132.7.5-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-psycopg2-debugbefore 2.7.5-7.module_el8.6.0+2781+fed64c132.7.5-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-psycopg2-testsbefore 2.7.5-7.module_el8.6.0+2781+fed64c132.7.5-7.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pybefore 1.5.3-6.module_el8.6.0+2781+fed64c131.5.3-6.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-PyMySQLbefore 0.8.0-10.module_el8.6.0+2781+fed64c130.8.0-10.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pysocksbefore 1.6.8-6.module_el8.6.0+2781+fed64c131.6.8-6.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pytestbefore 3.4.2-13.module_el8.6.0+2781+fed64c133.4.2-13.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pytest-mockbefore 1.9.0-4.module_el8.6.0+2781+fed64c131.9.0-4.module_el8.6.0+2781+fed64c13
AlmaLinux:8python2-pytzbefore 2017.2-12.module_el8.6.0+2781+fed64c132017.2-12.module_el8.6.0+2781+fed64c13

+96

Other highest-scoring records for the same primary product.

  • CVE-2016-5636Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 all
    47Plan
  • CVE-2007-4559Directory traversal vulnerability in the (1) extract and (2) extractall functions in the tarfile module in Python allows user-assisted remot
    47Plan
  • CVE-2021-3177Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Pyth
    46Plan
  • CVE-2014-4650The CGIHTTPServer module in Python 2.7.5 and 3.3.4 does not properly handle URLs in which URL encoding is used for path separators, which al
    46Plan
  • CVE-2018-1000802Python Software Foundation Python (CPython) version 2.7 contains a CWE-77: Improper Neutralization of Special Elements used in a Command ('C
    45Plan
  • CVE-2020-27619In Python 3 through 3.9.0, the Lib/test/multibytecodec_support.py CJK codec tests call eval() on content retrieved via HTTP.
    42Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:python-psycopg2-doc2.7.5-7.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-attrs17.4.0-10.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-chardet3.0.4-10.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-coverage4.5.1-4.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-Cython0.28.1-7.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-dns1.15.0-10.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-docs2.7.16-2.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-docs-info2.7.16-2.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-docutils0.14-12.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-funcsigs1.0.2-13.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-idna2.5-7.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
almalinux:python2-PyMySQL0.8.0-10.module_el8.6.0+2781+fed64c13 · AlmaLinux:8Package registry (OSV)
debian:python2.72.7.16-3 · Debian:11Package registry (OSV)
debian:python3.43.4.2-1+deb8u6 · Debian:8Package registry (OSV)
debian:python3.53.5.3-1+deb9u2 · Debian:9Package registry (OSV)
opensuse:python2.7.14-lp150.6.17.1 · openSUSE:Leap 15.0Package registry (OSV)
opensuse:python-base2.7.14-lp151.10.7.1 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:python-doc2.7.14-lp151.10.7.1 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:python33.6.10-lp151.6.7.1 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:python3-base3.6.10-lp151.6.7.1 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:python363.6.15-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:python27-python0:2.7.17-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:python27-python-debug0:2.7.17-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:python27-python-debuginfo0:2.7.17-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:python27-python-devel0:2.7.17-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:rh-python36-python0:3.6.9-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:rh-python36-python-debug0:3.6.9-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:rh-python36-python-debuginfo0:3.6.9-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:rh-python36-python-devel0:3.6.9-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)
red hat:rh-python36-python-libs0:3.6.9-2.el6 · Red Hat:rhel_software_collections:3::el6Package registry (OSV)

+22

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

nvd-secondary

Change log

  1. CVSS5.3 → 4.3
  2. SSVC exploitation— → none
  3. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records