MEDIUM 5.9 NVD
CVE-2026-84378
HTTPX2 is a next generation HTTP client for Python. From 2.5.0 until 2.10.0, the HTTPX2 Server-Sent Events parser in src/httpx2/httpx2/_sse.py repeatedly copies
HTTPX2 is a next generation HTTP client for Python. From 2.5.0 until 2.10.0, the HTTPX2 Server-Sent Events parser in src/httpx2/httpx2/_sse.py repeatedly copies and rescans buffered text in _SSELineDecoder.decode() when an attacker-controlled or compromised SSE endpoint splits one unterminated line across many response chunks. The behavior affects httpx2.Client.sse() and httpx2.AsyncClient.sse(), and the total processing work grows quadratically with the line length, allowing a crafted stream to consume excessive CPU and block a synchronous worker or asynchronous event loop. This issue is fixed in version 2.10.0.
References
- https://github.com/pydantic/httpx2/commit/cbfc0e04ef6507da29ccbb3b9c2e5b23dd693414
- https://github.com/pydantic/httpx2/pull/1071
- https://github.com/pydantic/httpx2/pull/1117
- https://github.com/pydantic/httpx2/releases/tag/v2.10.0
- https://github.com/pydantic/httpx2/security/advisories/GHSA-f2fp-rgf2-35cp
This medium severity vulnerability with a CVSS score of 5.9 was published on 2026-09-02 via NVD.
vulnfeed aggregates 10363 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.