{"id":"UBUNTU-CVE-2025-66418","details":"urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0.","modified":"2026-05-29T10:59:10.191897626Z","published":"2025-12-05T16:15:00Z","related":["USN-7927-1","USN-8010-1","USN-8344-1"],"upstream":["CVE-2025-66418"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-66418"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-66418"},{"type":"REPORT","url":"https://www.openwall.com/lists/oss-security/2025/12/05/4"},{"type":"REPORT","url":"https://github.com/urllib3/urllib3/security/advisories/GHSA-gm62-xv2j-4w53"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7927-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8010-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8344-1"}],"affected":[{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.25.8-2ubuntu0.4+esm2"}]}],"versions":["1.24.1-1ubuntu1","1.24.1-1ubuntu2","1.25.8-1","1.25.8-2","1.25.8-2ubuntu0.1","1.25.8-2ubuntu0.2","1.25.8-2ubuntu0.3","1.25.8-2ubuntu0.4","1.25.8-2ubuntu0.4+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.25.8-2ubuntu0.4+esm2","binary_name":"python3-urllib3"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.26.5-1~exp1ubuntu0.4"}]}],"versions":["1.26.5-1~exp1","1.26.5-1~exp1ubuntu0.1","1.26.5-1~exp1ubuntu0.2","1.26.5-1~exp1ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-urllib3","binary_version":"1.26.5-1~exp1ubuntu0.4"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-pip","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"22.0.2+dfsg-1ubuntu0.7+esm1"}]}],"versions":["20.3.4-4","21.3.1+dfsg-3","22.0.2+dfsg-1","22.0.2+dfsg-1ubuntu0.1","22.0.2+dfsg-1ubuntu0.2","22.0.2+dfsg-1ubuntu0.3","22.0.2+dfsg-1ubuntu0.4","22.0.2+dfsg-1ubuntu0.5","22.0.2+dfsg-1ubuntu0.6","22.0.2+dfsg-1ubuntu0.7"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-pip","binary_version":"22.0.2+dfsg-1ubuntu0.7+esm1"},{"binary_name":"python3-pip-whl","binary_version":"22.0.2+dfsg-1ubuntu0.7+esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.7-1ubuntu0.3"}]}],"versions":["1.26.16-1","1.26.18-1","2.0.7-1","2.0.7-1ubuntu0.1","2.0.7-1ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_version":"2.0.7-1ubuntu0.3","binary_name":"python3-urllib3"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-pip","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"24.0+dfsg-1ubuntu1.3+esm1"}]}],"versions":["23.2+dfsg-1","23.3+dfsg-1","24.0+dfsg-1","24.0+dfsg-1ubuntu1","24.0+dfsg-1ubuntu1.1","24.0+dfsg-1ubuntu1.2","24.0+dfsg-1ubuntu1.3"],"ecosystem_specific":{"binaries":[{"binary_version":"24.0+dfsg-1ubuntu1.3+esm1","binary_name":"python3-pip"},{"binary_version":"24.0+dfsg-1ubuntu1.3+esm1","binary_name":"python3-pip-whl"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-pip","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["25.0+dfsg-1","25.1.1+dfsg-1","25.1.1+dfsg-1ubuntu1","25.1.1+dfsg-1ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-pip","binary_version":"25.1.1+dfsg-1ubuntu2"},{"binary_version":"25.1.1+dfsg-1ubuntu2","binary_name":"python3-pip-whl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0-3ubuntu0.1"}]}],"versions":["2.3.0-2","2.3.0-2ubuntu1","2.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-urllib3","binary_version":"2.3.0-3ubuntu0.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.0-1ubuntu1"}]}],"versions":["2.3.0-3","2.5.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.5.0-1ubuntu1","binary_name":"python3-urllib3"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-66418.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}