What’s Vulnerable › Vulnerabilities

CVE-2026-84381: HTTPX2: Secure WebSocket traffic sent without TLS through SOCKS proxies

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-02 · updated 2026-09-09
• Weakness: CWE-319

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

• pydantic httpcore2: before 2.10.0
• pydantic httpx2: from 2.6.0, < 2.10.0

References

• https://github.com/pydantic/httpx2/commit/fb008dd700b761d955210d9692475c3e2f379453
• https://github.com/pydantic/httpx2/pull/1104
• https://github.com/pydantic/httpx2/releases/tag/v2.10.0
• https://github.com/pydantic/httpx2/security/advisories/GHSA-7mj9-2mp8-4m2p

Get alerted when CVE-2026-84381 or the next vulnerability affects your stack