{"answers":{"affected":"3 open source packages ship an affected version, including urllib3. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-21441 in the wild and no public exploit code.","fix":"Upgrade urllib3 to 2.6.3 or later.","what":"CVE-2026-21441 is a high-severity denial of service vulnerability in urllib3, published on 7 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21441 and fix it if it is affected.\n\nWhat it is: CVE-2026-21441 is a high-severity denial of service vulnerability in urllib3, published on 7 Jan 2026. 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-2026-21441 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- urllib3 (PyPI): affected from 1.22; fixed in 2.6.3\n- urllib3 (PyPI): affected from 1.22; fixed in 2.6.3\n- urllib3 (PyPI): affected from 1.22; fixed in 2.6.3\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-2026-21441/ (Markdown: https://insights.sbomify.com/CVE-2026-21441/index.md)","id":"CVE-2026-21441","markdown":"https://insights.sbomify.com/CVE-2026-21441/index.md","name":"CVE-2026-21441","record":{"aliases":["ALPINE-CVE-2026-21441","AZL-73730","AZL-73734","AZL-74153","BELL-CVE-2026-21441","CLEANSTART-2026-PK89488","CLEANSTART-2026-YM85365","CLSA-2026-1770682366","CLSA-2026-1791268253","DEBIAN-CVE-2026-21441","DLA-4446-1","DSA-6102-2","ECHO-48c0-4c3c-3a0d","GHSA-38jv-5279-wg99","MINI-2q2r-h864-f57h","MINI-3h9c-c825-jg4m","MINI-4497-2x62-4fx9","MINI-4mx3-83vw-v59h","MINI-5f63-rg2m-p9j6","MINI-cwgm-53c6-gr8g","MINI-fhg4-2q7p-cq54","MINI-hr78-cpr6-467g","MINI-m3p5-rx32-454w","MINI-mwpf-2jq5-22xw","MINI-pr9v-5mxq-gfww","MINI-q582-p53v-ccxp","MINI-w3xc-xhqg-3428","OESA-2026-1287","OESA-2026-1288","OESA-2026-1290","OESA-2026-1346","OESA-2026-1445","PYSEC-2026-1996","RHSA-2026:2911","ROOT-APP-PYPI-CVE-2026-21441","ROOT-OS-UBUNTU-2204-CVE-2026-21441","SUSE-SU-2026:0255-1","SUSE-SU-2026:0255-2","SUSE-SU-2026:20131-1","SUSE-SU-2026:20157-1","SUSE-SU-2026:20270-1","SUSE-SU-2026:20364-1","openSUSE-SU-2026:10049-1","openSUSE-SU-2026:20088-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Python HTTP client library","requires_auth":"none","summary":"Attackers can cause excessive resource consumption in Python applications using urllib3's streaming API with redirects enabled, leading to denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"urllib3","vendor":"python"}],"cvss":{"score":8.9,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H","version":"4.0"},"cwes":[{"id":"CWE-409","name":"Improper Handling of Highly Compressed Data (Data Amplification)"}],"description":"urllib3 is an HTTP client library for Python. urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. urllib3 can perform decoding or decompression based on the HTTP `Content-Encoding` header (e.g., `gzip`, `deflate`, `br`, or `zstd`). When using the streaming API, the library decompresses only the necessary bytes, enabling partial content consumption. Starting in version 1.22 and prior to version 2.6.3, for HTTP redirect responses, the library would read the entire response body to drain the connection and decompress the content unnecessarily. This decompression occurred even before any read methods were called, and configured read limits did not restrict the amount of decompressed data. As a result, there was no safeguard against decompression bombs. A malicious server could exploit this to trigger excessive resource consumption on the client. Applications and libraries are affected when they stream content from untrusted sources by setting `preload_content=False` when they do not disable redirects. Users should upgrade to at least urllib3 v2.6.3, in which the library does not decode content of redirect responses when `preload_content=False`. If upgrading is not immediately possible, disable redirects by setting `redirect=False` for requests to untrusted source.","ecosystems":["PyPI","Red Hat:enterprise_linux:7::server","SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS","SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS","SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS","SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS","SUSE:Linux Enterprise Module for Public Cloud 15 SP4","SUSE:Linux Enterprise Module for Python 3 15 SP7","SUSE:Linux Enterprise Server 15 SP4-LTSS","SUSE:Linux Enterprise Server 15 SP5-LTSS","SUSE:Linux Enterprise Server 15 SP6-LTSS","SUSE:Linux Enterprise Server 16.0","SUSE:Linux Enterprise Server for SAP Applications 15 SP4","SUSE:Linux Enterprise Server for SAP Applications 15 SP5","SUSE:Linux Enterprise Server for SAP Applications 15 SP6","SUSE:Linux Enterprise Server for SAP applications 16.0","SUSE:Linux Micro 6.0","SUSE:Linux Micro 6.1","SUSE:Linux Micro 6.2","openSUSE:Leap 15.6","openSUSE:Leap 16.0","openSUSE:Tumbleweed"],"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":"urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API)","id":"CVE-2026-21441","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":24,"n_references":2,"next":{"headline":"OpenEMR allows inconsistent escaping of translation function output","id":"CVE-2026-21443"},"packages":[{"ecosystem":"PyPI","fixed":["2.6.3"],"introduced":["1.22"],"last_affected":[],"package":"urllib3","purl":null,"source":"GHSA-38jv-5279-wg99"},{"ecosystem":"PyPI","fixed":["2.6.3"],"introduced":["1.22"],"last_affected":[],"package":"urllib3","purl":"pkg:pypi/urllib3","source":"GHSA-38jv-5279-wg99"},{"ecosystem":"PyPI","fixed":["2.6.3"],"introduced":["1.22"],"last_affected":[],"package":"urllib3","purl":"pkg:pypi/urllib3","source":"PYSEC-2026-1996"},{"ecosystem":"Red Hat:enterprise_linux:7::server","fixed":["0:0.1.13-1.el7_9.6"],"introduced":["0"],"last_affected":[],"package":"python-s3transfer","purl":"pkg:rpm/redhat/python-s3transfer","source":"RHSA-2026:2911"},{"ecosystem":"SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP4-ESPOS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP4-LTSS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP5-ESPOS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP5-LTSS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Module for Public Cloud 15 SP4","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2015%20SP4","source":"SUSE-SU-2026:0255-1"},{"ecosystem":"SUSE:Linux Enterprise Module for Python 3 15 SP7","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Module%20for%20Python%203%2015%20SP7","source":"SUSE-SU-2026:0255-1"},{"ecosystem":"SUSE:Linux Enterprise Server 15 SP4-LTSS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP4-LTSS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server 15 SP5-LTSS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP5-LTSS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server 15 SP6-LTSS","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP6-LTSS","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server 16.0","fixed":["2.5.0-160000.3.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%2016.0","source":"SUSE-SU-2026:20131-1"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 15 SP4","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP4","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 15 SP5","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP5","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 15 SP6","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP6","source":"SUSE-SU-2026:0255-2"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","fixed":["2.5.0-160000.3.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20applications%2016.0","source":"SUSE-SU-2026:20131-1"},{"ecosystem":"SUSE:Linux Micro 6.0","fixed":["2.1.0-4.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Micro%206.0","source":"SUSE-SU-2026:20270-1"},{"ecosystem":"SUSE:Linux Micro 6.1","fixed":["2.1.0-slfo.1.1_3.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Micro%206.1","source":"SUSE-SU-2026:20364-1"},{"ecosystem":"SUSE:Linux Micro 6.2","fixed":["2.5.0-160000.3.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/suse/python-urllib3\u0026distro=SUSE%20Linux%20Micro%206.2","source":"SUSE-SU-2026:20157-1"},{"ecosystem":"openSUSE:Leap 15.6","fixed":["2.0.7-150400.7.24.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/opensuse/python-urllib3\u0026distro=openSUSE%20Leap%2015.6","source":"SUSE-SU-2026:0255-1"},{"ecosystem":"openSUSE:Leap 16.0","fixed":["2.5.0-160000.3.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/opensuse/python-urllib3\u0026distro=openSUSE%20Leap%2016.0","source":"openSUSE-SU-2026:20088-1"},{"ecosystem":"openSUSE:Tumbleweed","fixed":["2.6.3-1.1"],"introduced":["0"],"last_affected":[],"package":"python-urllib3","purl":"pkg:rpm/opensuse/python-urllib3\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2026:10049-1"}],"prev":{"headline":"AdonisJS Path Traversal in Multipart File Handling","id":"CVE-2026-21440"},"products":["urllib3"],"published":"2026-01-07","related":[{"cvss_score":8.9,"headline":"urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory","id":"CVE-2026-97689","kev_date_added":null,"published":"2026-09-29"},{"cvss_score":8.9,"headline":"urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API","id":"CVE-2026-44432","kev_date_added":null,"published":"2026-05-13"},{"cvss_score":8.9,"headline":"urllib3 allows an unbounded number of links in the decompression chain","id":"CVE-2025-66418","kev_date_added":null,"published":"2025-12-05"},{"cvss_score":8.9,"headline":"urllib3 Streaming API improperly handles highly compressed data","id":"CVE-2025-66471","kev_date_added":null,"published":"2025-12-05"},{"cvss_score":8.2,"headline":"urllib3: Sensitive headers forwarded across origins in proxied low-level redirects","id":"CVE-2026-44431","kev_date_added":null,"published":"2026-05-13"},{"cvss_score":7.6,"headline":"urllib3: HTTPS proxy TLS configuration may be ignored or overridden","id":"CVE-2026-97687","kev_date_added":null,"published":"2026-09-29"}],"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":"RHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"SUSE"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-17","vendors":["urllib3"]},"summary":"Attackers can cause excessive resource consumption in Python applications using urllib3's streaming API with redirects enabled, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2026-21441/"}