Jens Geyer created THRIFT-6089:
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Summary: Bound decompressed size for Ruby HeaderTransport ZLIB
transform
Key: THRIFT-6089
URL: https://issues.apache.org/jira/browse/THRIFT-6089
Project: Thrift
Issue Type: Bug
Components: Ruby - Library
Reporter: Jens Geyer
Fix For: 0.24.0
parse_header_format in header_transport.rb applied
Zlib::Inflate.inflate(payload) to the ZLIB transform with no limit on the
decompressed output size. The existing frame-size check bounded only the
compressed wire frame. The reporter's proof-of-concept demonstrated a 1020:1
amplification ratio (a ~2KB compressed frame producing a ~2MB allocation) with
no authentication gate before the code path.
Fixed by replacing the one-shot inflate with a streaming loop that accumulates
decompressed bytes and raises TransportException once a configurable
@max_decompressed_size (default MAX_FRAME_SIZE) is exceeded, mirroring the
Python fix (CVE-2026-41608).
*Affects:* Ruby HeaderTransport with ZLIB transform support, confirmed present
in 0.23.0; fixed in 0.24.0
*Fixed by:* branch {{ruby-header-zlib-limit}}, PR #3547
*CWE-409:* Improper Handling of Highly Compressed Data (Data Amplification)
*CVSS 4.0:* 8.7 High
({{CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N}})
*Reported by:* LTSHFWJT, via [email protected]
*CVE:* CVE-2026-49158
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