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...

Chainlist has SSRF via MCP SSE and streamable-http transports that allows unauthenticated internal network access

Am I affected?Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. SummaryWhen MCP is...

SUSE CVE-2026-86252

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

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...

EUVD-2026-70242

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

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...

Inefficient Algorithmic Complexity

Overview httpx2 is a The next generation HTTP client. Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity through the sse. An attacker can cause excessive CPU consumption by sending a long, unterminated line split across many small response chunks from a...

Stream Corruption

Spring Framework is vulnerable to stream corruption. The vulnerability is due to improper handling of response streams when processing SSE with view fragments, which allows an attacker to potentially corrupt or disrupt the application’s HTTP response stream...

CVE-2026-86252

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

CVE-2026-86252 h3 before 1.15.9 SSE Event Injection via Carriage Return

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

CVE-2026-86252 h3 before 1.15.9 SSE Event Injection via Carriage Return

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

CVE-2026-86252

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, enabling attackers to inject arbitrary SSE events . The flaw allows injection of event type directives, splitting a single push call into multiple browser-parsed events, or escaping comme...

CVE-2026-86252 h3 before 1.15.9 SSE Event Injection via Carriage Return

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

PT-2026-86521

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

CVE-2026-86252: Improper Neutralization of Special Elements in Output Used by a Downstream Component

h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-pars...

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: 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...