{"answers":{"affected":"3 open source packages ship an affected version, including urllib3. It affects 3 products.","exploited":"There is no known exploitation of CVE-2021-28363 in the wild and no public exploit code.","fix":"Upgrade urllib3 to 1.26.4 or later.","what":"CVE-2021-28363 is a medium-severity vulnerability in Fedoraproject Fedora, published on 15 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-28363 and fix it if it is affected.\n\nWhat it is: CVE-2021-28363 is a medium-severity vulnerability in Fedoraproject Fedora, published on 15 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-28363 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- urllib3 (PyPI): affected from 1.26.0; fixed in 1.26.4\n- urllib3 (PyPI): affected from 1.26.0; fixed in 1.26.4\n- urllib3 (PyPI): affected from 1.26.0; fixed in 1.26.4\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-28363/ (Markdown: https://insights.sbomify.com/CVE-2021-28363/index.md)","id":"CVE-2021-28363","markdown":"https://insights.sbomify.com/CVE-2021-28363/index.md","name":"CVE-2021-28363","record":{"aliases":["ALPINE-CVE-2021-28363","CLEANSTART-2026-AK39245","CLEANSTART-2026-MO57102","DEBIAN-CVE-2021-28363","GHSA-5phf-pp7p-vc2r","PYSEC-2021-59","RHBA-2021:1147","ROOT-APP-PYPI-CVE-2021-28363"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"Python HTTP library","requires_auth":"none","summary":"Attackers can bypass SSL certificate validation when using HTTPS proxies without a custom SSLContext, allowing man-in-the-middle attacks.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mitre","cpe":[{"product":"fedora","vendor":"fedoraproject"},{"product":"peoplesoft_enterprise_peopletools","vendor":"oracle"},{"product":"urllib3","vendor":"python"}],"cvss":{"score":6.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-295","name":"Improper Certificate Validation"}],"description":"The urllib3 library 1.26.x before 1.26.4 for Python omits SSL certificate validation in some cases involving HTTPS to HTTPS proxies. The initial connection to the HTTPS proxy (if an SSLContext isn't given via proxy_config) doesn't verify the hostname of the certificate. This means certificates for different servers that still validate properly with the default urllib3 SSLContext will be silently accepted.","ecosystems":["PyPI","Red Hat:openshift:3.11::el7"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Using default SSLContext for HTTPS requests in an HTTPS proxy doesn't verify certificate hostname for proxy connection","id":"CVE-2021-28363","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":"fedoraproject:fedora","products":["fedoraproject:fedora","oracle:peoplesoft_enterprise_peopletools"],"type":"security_feature_bypass","year":"2021"},"n_packages":5,"n_references":9,"next":{"headline":"Auth bypass in n/a","id":"CVE-2021-28372"},"packages":[{"ecosystem":"PyPI","fixed":["1.26.4"],"introduced":["1.26.0"],"last_affected":[],"package":"urllib3","purl":null,"source":"GHSA-5phf-pp7p-vc2r"},{"ecosystem":"PyPI","fixed":["1.26.4"],"introduced":["1.26.0"],"last_affected":[],"package":"urllib3","purl":"pkg:pypi/urllib3","source":"GHSA-5phf-pp7p-vc2r"},{"ecosystem":"PyPI","fixed":["1.26.4"],"introduced":["1.26.0"],"last_affected":[],"package":"urllib3","purl":"pkg:pypi/urllib3","source":"PYSEC-2021-59"},{"ecosystem":"Red Hat:openshift:3.11::el7","fixed":["1:1.24.3-2.el7"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/redhat/python-urllib3","source":"RHBA-2021:1147"},{"ecosystem":"Red Hat:openshift:3.11::el7","fixed":["1:1.24.3-2.el7"],"introduced":["0"],"last_affected":[],"package":"python2-urllib3","purl":"pkg:rpm/redhat/python2-urllib3","source":"RHBA-2021:1147"}],"prev":{"headline":"Integer overflow in n/a","id":"CVE-2021-28362"},"products":["n/a"],"published":"2021-03-15","related":[{"cvss_score":9.8,"headline":"PHP-CGI OS Command Injection","id":"CVE-2024-4577","kev_date_added":"2024-06-12","published":"2024-06-09"},{"cvss_score":9.8,"headline":"Grafana Authentication Bypass","id":"CVE-2021-39226","kev_date_added":"2022-08-25","published":"2021-10-05"},{"cvss_score":9.8,"headline":"VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow","id":"CVE-2019-5544","kev_date_added":"2021-11-03","published":"2019-12-06"},{"cvss_score":9.6,"headline":"Google Chromium V8 Type Confusion","id":"CVE-2024-4947","kev_date_added":"2024-05-20","published":"2024-05-15"},{"cvss_score":9.6,"headline":"Google Chromium Visuals Use-After-Free","id":"CVE-2024-4671","kev_date_added":"2024-05-13","published":"2024-05-09"},{"cvss_score":9.6,"headline":"Google Chromium Mojo Insufficient Data Validation","id":"CVE-2022-3075","kev_date_added":"2022-09-08","published":"2022-09-26"},{"cvss_score":9.6,"headline":"Google Chromium Indexed DB API Use-After-Free","id":"CVE-2021-30633","kev_date_added":"2021-11-03","published":"2021-10-08"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"CC BY 4.0","name":"Red Hat","prefix":"RHBA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-14","vendors":["n/a"]},"summary":"Attackers can bypass SSL certificate validation when using HTTPS proxies without a custom SSLContext, allowing man-in-the-middle attacks.","url":"https://insights.sbomify.com/CVE-2021-28363/"}