CVE-2026-84381: high-severity vulnerability in pydantic httpx2
HTTPX2: Secure WebSocket traffic sent without TLS through SOCKS proxies
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.1epss 0.1%
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.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Related CVEs — pydantic httpx2
In the same product, most dangerous first.
CVE-2026-84382HIGHHTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)EPSS 0.6%CVE-2026-84379MEDIUMHTTPX2: Multipart part header injection via unvalidated file Content-Type and custom headersEPSS 0.3%CVE-2026-84378MEDIUMHTTPX2: Quadratic SSE line buffering can cause CPU denial of serviceEPSS 0.3%CVE-2026-84380MEDIUMHTTPX2: Conflicting Content-Length and Transfer-Encoding headers can be auto-generatedEPSS 0.2%