Security update for python-urllib3 SUSE Patch security@suse.de SUSE Security Team SUSE-SU-2026:20364-1 Final 1 1 2026-01-21T13:44:58Z current 2026-01-21T13:44:58Z 2026-01-21T13:44:58Z cve-database/bin/generate-cvrf.pl 2017-02-24T01:00:00Z Security update for python-urllib3 This update for python-urllib3 fixes the following issues: - CVE-2026-21441: Fixed excessive resource consumption during decompression of data in HTTP redirect responses (bsc#1256331). The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). SUSE-SLE-Micro-6.1-382 Copyright SUSE LLC under the Creative Commons License 4.0 with Attribution (CC-BY-4.0) https://www.suse.com/support/update/announcement/2026/suse-su-202620364-1/ Link for SUSE-SU-2026:20364-1 https://lists.suse.com/pipermail/sle-security-updates/2026-February/024321.html E-Mail link for SUSE-SU-2026:20364-1 https://www.suse.com/support/security/rating/ SUSE Security Ratings https://bugzilla.suse.com/1256331 SUSE Bug 1256331 https://www.suse.com/security/cve/CVE-2026-21441/ SUSE CVE CVE-2026-21441 page SUSE Linux Micro 6.1 python311-urllib3-2.1.0-slfo.1.1_3.1 python311-urllib3-2.1.0-slfo.1.1_3.1 as a component of SUSE Linux Micro 6.1 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. CVE-2026-21441 SUSE Linux Micro 6.1:python311-urllib3-2.1.0-slfo.1.1_3.1 moderate To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch". https://www.suse.com/support/update/announcement/2026/suse-su-202620364-1/ https://www.suse.com/security/cve/CVE-2026-21441.html CVE-2026-21441 https://bugzilla.suse.com/1256331 SUSE Bug 1256331