HTTPX2: Quadratic SSE line buffering can cause CPU denial of service

SummaryHTTPX2's Server-Sent Events SSE parser repeatedly copied and rescanned buffered text when a server split one unterminated line across many response chunks. The total work grows quadratically with the length of the line. An attacker-controlled or compromised SSE endpoint can exploit this...

GHSA-F2FP-RGF2-35CP HTTPX2: Quadratic SSE line buffering can cause CPU denial of service

Summary HTTPX2's Server-Sent Events SSE parser repeatedly copied and rescanned buffered text when a server split one unterminated line across many response chunks. The total work grows quadratically with the length of the line. An attacker-controlled or compromised SSE endpoint can exploit this...

Linux Distros Unpatched Vulnerability : CVE-2026-84378

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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...

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 and rescans buffered text in SSELineDecoder.decode when an attacker-controlled or compromised SSE endpoint splits one unterminated line...

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 and rescans buffered text in SSELineDecoder.decode when an attacker-controlled or compromised SSE endpoint splits one unterminated line...

CVE-2026-84378

HTTPX2 , a next-generation HTTP client for Python, is affected by a quadratic CPU denial-of-service vulnerability in its Server-Sent Events (SSE) parser. Versions from 2.5.0 through 2.10.0 are impacted. The root cause lies in _SSELineDecoder.decode() in src/httpx2/httpx2/_sse.py, which repeatedly...

CVE-2026-84378 HTTPX2: Quadratic SSE line buffering can cause CPU denial of service

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...

CVE-2026-84378 HTTPX2: Quadratic SSE line buffering can cause CPU denial of service

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...

PT-2026-84844

Name of the Vulnerable Software and Affected Versions HTTPX2 versions 2.5.0 through 2.9.0 Description The Server-Sent Events SSE parser in src/httpx2/httpx2/ sse.py repeatedly copies and rescans buffered text within the SSELineDecoder.decode function when an SSE endpoint splits a single...