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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-49855

tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)

Description

Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

tornadoweb tornado

  • < 6.5.6affected

References