{"id":"CVE-2026-84382","aliases":["DEBIAN-CVE-2026-84382","EUVD-2026-70251","GHSA-8xx6-hgc6-gc2m","PYSEC-2026-3846","UBUNTU-CVE-2026-84382"],"status":"published","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0063,"percentile":0.50647,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-409"],"published":"2026-09-02T18:03:05Z","modified":"2026-10-28T02:30:48Z","fixes":[{"ecosystem":"PyPI","package":"httpx2","fixed_in":["2.12.0"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:14","package":"python-httpx2","fixed_in":["2.12.0-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"httpx2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.12.0"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"python-httpx2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.12.0-1"}]}],"versions":["2.4.0-1","2.5.0-1"]},{"source":"osv","ecosystem":"PyPI","package":"httpx2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.12.0"}]}],"versions":["0.0.0","2.0.0","2.0.0b1","2.1.0","2.10.0","2.11.0","2.2.0","2.3.0","2.4.0","2.5.0","2.6.0","2.7.0","2.8.0","2.9.0","2.9.1"]},{"source":"osv","ecosystem":"PyPI","package":"httpx2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.12.0"}]}],"versions":["0.0.0","2.0.0","2.0.0b1","2.1.0","2.10.0","2.11.0","2.2.0","2.3.0","2.4.0","2.5.0","2.6.0","2.7.0","2.8.0","2.9.0","2.9.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"python-httpx2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.0-1"]}],"products":[{"vendor":"pydantic","product":"httpx2"}],"references":[{"url":"https://github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2m","tags":["x_refsource_CONFIRM","advisory","web","report"]},{"url":"https://github.com/pydantic/httpx2/pull/1126","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/pydantic/httpx2/releases/tag/v2.12.0","tags":["x_refsource_MISC","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84382","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-8xx6-hgc6-gc2m","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84382.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-84382","tags":["advisory"]},{"url":"https://github.com/pydantic/httpx2","tags":["package"]},{"url":"https://pypi.org/project/httpx2","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-84382","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-84382","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-84382","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T18:03:05.01Z","modified":"2026-09-03T14:31:19.366Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:20:08.391556Z"}],"euvd":[{"id":"EUVD-2026-70251","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T18:03:05Z","modified":"2026-09-03T14:31:19Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T18:01:13.671159Z"}],"ghsa":[{"id":"GHSA-8xx6-hgc6-gc2m","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"### Summary\n\nWhen decoding a compressed response body (`gzip`, `deflate`, `br`, or `zstd`), HTTPX2 fully decompressed each network read before yielding content to the application. A small compressed input could therefore cause a large intermediate memory allocation, even when the application streamed the response to keep memory usage bounded.\n\n### Details\n\nHTTPX2's default transport reads the socket in pieces of up to 64 KiB. Before `2.12.0`, each piece was inflated completely into one intermediate allocation before any decompressed bytes were yielded.\n\nAt DEFLATE's maximum compression ratio of roughly 1032:1, a 64 KiB compressed chunk can expand to about 64 MiB in one allocation. Brotli and Zstandard responses can cause similarly large amplification. Streaming the response did not prevent these transient allocations.\n\n### Impact\n\nApplications that fetch resources from untrusted or attacker-influenced servers - such as webhook receivers, link unfurlers, crawlers, SSRF-reachable fetchers, and redirect followers - can experience memory pressure or out-of-memory termination when processing a malicious compressed response. No authentication or user interaction is required beyond issuing a request to the server.\n\n### Mitigation\n\nUpgrade to HTTPX2 `2.12.0` or later. Patched versions decompress responses incrementally with bounded intermediate buffers, including responses with multiple content encodings.","status":"published","published":"2026-09-08T20:48:59Z","modified":"2026-09-08T20:48:59Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:41:14.764963Z"}],"nvd":[{"id":"CVE-2026-84382","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T19:18:08.353Z","modified":"2026-09-09T21:05:23.237Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T14:12:43.399612Z"}],"osv":[{"id":"CVE-2026-84382","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T18:03:05.01Z","modified":"2026-10-28T02:30:48.138781181Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T15:45:18.482949Z"},{"id":"DEBIAN-CVE-2026-84382","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T19:18:08.353Z","modified":"2026-10-01T03:03:37.337340898Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:46:04.577397Z"},{"id":"GHSA-8xx6-hgc6-gc2m","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"### Summary\n\nWhen decoding a compressed response body (`gzip`, `deflate`, `br`, or `zstd`), HTTPX2 fully decompressed each network read before yielding content to the application. A small compressed input could therefore cause a large intermediate memory allocation, even when the application streamed the response to keep memory usage bounded.\n\n### Details\n\nHTTPX2's default transport reads the socket in pieces of up to 64 KiB. Before `2.12.0`, each piece was inflated completely into one intermediate allocation before any decompressed bytes were yielded.\n\nAt DEFLATE's maximum compression ratio of roughly 1032:1, a 64 KiB compressed chunk can expand to about 64 MiB in one allocation. Brotli and Zstandard responses can cause similarly large amplification. Streaming the response did not prevent these transient allocations.\n\n### Impact\n\nApplications that fetch resources from untrusted or attacker-influenced servers - such as webhook receivers, link unfurlers, crawlers, SSRF-reachable fetchers, and redirect followers - can experience memory pressure or out-of-memory termination when processing a malicious compressed response. No authentication or user interaction is required beyond issuing a request to the server.\n\n### Mitigation\n\nUpgrade to HTTPX2 `2.12.0` or later. Patched versions decompress responses incrementally with bounded intermediate buffers, including responses with multiple content encodings.","status":"published","published":"2026-09-08T20:48:59Z","modified":"2026-09-10T12:26:04.899389228Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-409"],"updated_at":"2026-11-02T15:46:43.123867Z"},{"id":"PYSEC-2026-3846","title":"HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)","description":"### Summary\n\nWhen decoding a compressed response body (`gzip`, `deflate`, `br`, or `zstd`), HTTPX2 fully decompressed each network read before yielding content to the application. A small compressed input could therefore cause a large intermediate memory allocation, even when the application streamed the response to keep memory usage bounded.\n\n### Details\n\nHTTPX2's default transport reads the socket in pieces of up to 64 KiB. Before `2.12.0`, each piece was inflated completely into one intermediate allocation before any decompressed bytes were yielded.\n\nAt DEFLATE's maximum compression ratio of roughly 1032:1, a 64 KiB compressed chunk can expand to about 64 MiB in one allocation. Brotli and Zstandard responses can cause similarly large amplification. Streaming the response did not prevent these transient allocations.\n\n### Impact\n\nApplications that fetch resources from untrusted or attacker-influenced servers - such as webhook receivers, link unfurlers, crawlers, SSRF-reachable fetchers, and redirect followers - can experience memory pressure or out-of-memory termination when processing a malicious compressed response. No authentication or user interaction is required beyond issuing a request to the server.\n\n### Mitigation\n\nUpgrade to HTTPX2 `2.12.0` or later. Patched versions decompress responses incrementally with bounded intermediate buffers, including responses with multiple content encodings.","status":"published","published":"2026-09-10T09:45:01.110644Z","modified":"2026-09-10T12:15:05.042801702Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:52:57.255153Z"},{"id":"UBUNTU-CVE-2026-84382","description":"HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.","status":"published","published":"2026-09-02T19:18:00Z","modified":"2026-10-17T13:01:12.715367392Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T16:57:22.213888Z"}]}}