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OpenAdvisories
High · 8.1 CVE-2026-84381 EUVD-2026-70250GHSA-7mj9-2mp8-4m2pPYSEC-2026-3844PYSEC-2026-3845

HTTPX2: Secure WebSocket traffic sent without TLS through SOCKS proxies

Published Sep 2, 2026 · Updated Sep 5, 2026 · Assigned by GitHub_M

Description

HTTPX2 is a next generation HTTP client for Python. Prior to 2.10.0, httpcore2 fails to start TLS in src/httpcore2/httpcore2/_sync/socks_proxy.py and src/httpcore2/httpcore2/_async/socks_proxy.py when the remote origin uses wss through a SOCKS5 proxy because the TLS upgrade condition only recognizes https. HTTPX2 exposes the flaw through Client.websocket() and AsyncClient.websocket() from 2.6.0 through 2.9.1, so the opening handshake, query parameters, Authorization headers, cookies, and subsequent frames can cross the proxy path in plaintext without certificate verification. An attacker controlling or observing that path can read or modify traffic and impersonate the WebSocket server. This issue is fixed in httpcore2 2.10.0 and HTTPX2 2.10.0.

Affected products

VendorProductAffectedFixed
pydantic httpx2 >= 2.6.0, < 2.10.0 —
pydantic httpcore2 < 2.10.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Ubuntu 26.10 python-httpx2 No fix yet —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI httpcore2 < 2.10.0 2.10.0 GHSA-7mj9-2mp8-4m2p
PyPI httpx2 >= 2.6.0, < 2.10.0 2.10.0 GHSA-7mj9-2mp8-4m2p

References