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. Applicat...

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. Application

urllib3 is an HTTP client library for Python. urllib3's streaming API ...

Security update for python-urllib3

Security update for python-urllib3

Decompression-bomb safeguards bypassed when following HTTP redirects (streaming API)

ELSA-2026-1254: python-urllib3 security update (IMPORTANT)

ELSA-2026-1241: resource-agents security update (IMPORTANT)

ELSA-2026-1240: fence-agents security update (IMPORTANT)

ELSA-2026-1239: fence-agents security update (IMPORTANT)

ELSA-2026-1226: python3.12-urllib3 security update (IMPORTANT)

ELSA-2026-1224: python3.11-urllib3 security update (IMPORTANT)

ELSA-2026-1089: python3.11-urllib3 security update (IMPORTANT)

ELSA-2026-1088: python3.12-urllib3 security update (IMPORTANT)

ELSA-2026-1087: python-urllib3 security update (IMPORTANT)

ELSA-2026-1086: python-urllib3 security update (IMPORTANT)