{"id":"UBUNTU-CVE-2026-97688","details":"urllib3 is an HTTP client library for Python. From 2.6.2 until 2.8.0, HTTPResponse.stream and HTTPResponse.read_chunked can enter an infinite loop because the Deflate decoder retains trailing bytes as unconsumed input after reaching end-of-stream and repeatedly decodes them without progress. The issue occurs when an untrusted server sends a chunked Deflate response whose decoded body exceeds a positive finite chunk size and whose encoded body has trailing bytes, specifically a response with Transfer-Encoding: chunked and Content-Encoding: deflate, content decoding enabled, and the positive finite amt=N streaming chunk size. The attack mechanism is that a malicious server returns a compressed chunked response with trailing bytes after the Deflate stream. The impact is excessive CPU usage and a request that does not complete, and network read timeouts do not interrupt the loop because no further socket read occurs. This issue is fixed in version 2.8.0.","modified":"2026-10-01T00:22:47.081698860Z","published":"2026-09-29T16:17:00Z","upstream":["CVE-2026-97688"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-97688"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-97688"},{"type":"REPORT","url":"https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g"},{"type":"REPORT","url":"https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f"},{"type":"REPORT","url":"https://github.com/urllib3/urllib3/releases/tag/2.8.0"}],"affected":[{"package":{"name":"python-pip","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.1-2","1.5.4-1","1.5.4-1ubuntu1","1.5.4-1ubuntu3","1.5.4-1ubuntu4","1.5.4-1ubuntu4+esm1","1.5.4-1ubuntu4+esm2","1.5.4-1ubuntu4+esm3","1.5.4-1ubuntu4+esm4","1.5.4-1ubuntu4+esm5"],"ecosystem_specific":{"binaries":[{"binary_version":"1.5.4-1ubuntu4+esm5","binary_name":"python-pip"},{"binary_version":"1.5.4-1ubuntu4+esm5","binary_name":"python-pip-whl"},{"binary_name":"python3-pip","binary_version":"1.5.4-1ubuntu4+esm5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-97688.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6-2","1.7.1-1","1.7.1-1build1","1.7.1-1ubuntu0.1","1.7.1-1ubuntu3","1.7.1-1ubuntu4","1.7.1-1ubuntu4.1","1.7.1-1ubuntu4.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.7.1-1ubuntu4.1+esm1","binary_name":"python-urllib3"},{"binary_version":"1.7.1-1ubuntu4.1+esm1","binary_name":"python-urllib3-whl"},{"binary_name":"python3-urllib3","binary_version":"1.7.1-1ubuntu4.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-97688.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.11-1","1.12-1","1.13.1-1","1.13.1-2","1.13.1-2ubuntu0.16.04.1","1.13.1-2ubuntu0.16.04.2","1.13.1-2ubuntu0.16.04.3","1.13.1-2ubuntu0.16.04.4","1.13.1-2ubuntu0.16.04.4+esm1","1.13.1-2ubuntu0.16.04.4+esm2","1.13.1-2ubuntu0.16.04.4+esm3","1.13.1-2ubuntu0.16.04.4+esm4"],"ecosystem_specific":{"binaries":[{"binary_name":"python-urllib3","binary_version":"1.13.1-2ubuntu0.16.04.4+esm4"},{"binary_name":"python3-urllib3","binary_version":"1.13.1-2ubuntu0.16.04.4+esm4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-97688.json"}},{"package":{"name":"python-pip","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.6-7ubuntu1","1.5.6-7ubuntu2","8.0.2-7","8.0.3-1","8.0.3-2","8.1.0-1","8.1.0-2","8.1.1-1","8.1.1-2","8.1.1-2ubuntu0.1","8.1.1-2ubuntu0.2","8.1.1-2ubuntu0.4","8.1.1-2ubuntu0.6","8.1.1-2ubuntu0.6+esm2","8.1.1-2ubuntu0.6+esm3","8.1.1-2ubuntu0.6+esm4","8.1.1-2ubuntu0.6+esm5","8.1.1-2ubuntu0.6+esm6","8.1.1-2ubuntu0.6+esm8","8.1.1-2ubuntu0.6+esm10","8.1.1-2ubuntu0.6+esm11","8.1.1-2ubuntu0.6+esm12"],"ecosystem_specific":{"binaries":[{"binary_name":"python-pip","binary_version":"8.1.1-2ubuntu0.6+esm12"},{"binary_name":"python-pip-whl","binary_version":"8.1.1-2ubuntu0.6+esm12"},{"binary_name":"python3-pip","binary_version":"8.1.1-2ubuntu0.6+esm12"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-97688.json"}},{"package":{"name":"python-urllib3","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/python-urllib3?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.21.1-1","1.22-1","1.22-1ubuntu0.18.04.1","1.22-1ubuntu0.18.04.2","1.22-1ubuntu0.18.04.2+esm1","1.22-1ubuntu0.18.04.2+esm2","1.22-1ubuntu0.18.04.2+esm3","1.22-1ubuntu0.18.04.2+esm4"],"ecosystem_specific":{"binaries":[{"binary_version":"1.22-1ubuntu0.18.04.2+esm4","binary_name":"python-urllib3"},{"binary_name":"python3-urllib3","binary_version":"1.22-1ubuntu0.18.04.2+esm4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-97688.json"}},{"package":{"name":"python-pip","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/python-pip?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.0.1-2","9.0.1-2.3~ubuntu1","9.0.1-2.3~ubuntu1.18.04.1","9.0.1-2.3~ubuntu1.18.04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