io.netty/netty-codec-http: Netty: Protocol version confusion in netty-codec-http (WebSocket)

A flaw was found in netty-codec-http. The WebSocket handshaker in this component fails to properly validate protocol version information during the WebSocket upgrade process. A remote attacker can exploit this vulnerability by manipulating the WebSocket handshake, leading to a bypass of security...

CVE-2026-66299

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web...

Fixed in Apache Tomcat 9.0.121

Low: DoS in WebSocket chat example CVE-2026-66299 The WebSocket chat example provided an unbounded buffer for undelivered messages. A maliciously slow client could cause the buffer to grow continuously, eventually leading to an memory exhaustion and failure of the Tomcat process. This was fixed...

EUVD-2026-49855

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web...

Fixed in Apache Tomcat 10.1.58

Low: DoS in WebSocket chat example CVE-2026-66299 The WebSocket chat example provided an unbounded buffer for undelivered messages. A maliciously slow client could cause the buffer to grow continuously, eventually leading to an memory exhaustion and failure of the Tomcat process. This was fixed...

Fixed in Apache Tomcat 11.0.25

Low: DoS in WebSocket chat example CVE-2026-66299 The WebSocket chat example provided an unbounded buffer for undelivered messages. A maliciously slow client could cause the buffer to grow continuously, eventually leading to an memory exhaustion and failure of the Tomcat process. This was fixed...

CVE-2026-66299

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web...

CVE-2026-66299

Summary: CVE-2026-66299 describes an Uncontrolled Resource Consumption (DoS) in Apache Tomcat’s WebSocket chat example. The vulnerability affects Tomcat versions 11.0.0-M20 through 11.0.24, 10.1.24 through 10.1.57, and 9.0.89 through 9.0.120. The root cause is an unbounded buffer for undelivered ...

CVE-2026-66299 Apache Tomcat: DoS via WebSocket chat example

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web...

CVE-2026-59898

A flaw was found in netty-codec-http. The WebSocket handshaker in this component fails to properly validate protocol version information during the WebSocket upgrade process. A remote attacker can exploit this vulnerability by manipulating the WebSocket handshake, leading to a bypass of security...

GHSA-7PPR-R889-MCF2 blaze: Unbounded WebSocket message aggregation in http4s-blaze-server

Summary http4s-blaze-server aggregates the fragments of an incoming WebSocket message with no limit on total size or fragment count. A client that completes a WebSocket handshake can send an unterminated fragmented message and drive unbounded heap growth in the server JVM, resulting in denial of...

GHSA-J657-M4C4-24JQ Open WebUI: Terminal proxy forwards a spoofable, integrity-unbound user identity to the upstream (X-User-Id header and ws_terminal session_id query injection)

Summary The terminal proxy in backend/openwebui/routers/terminals.py forwards the Open WebUI user's identity to the upstream terminal server / backend coordinator as an authorization claim, with no cryptographic binding to the session that produced it. The forwarded identity is...

CVE-2026-65623

Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversizemessage?/2 called from handleframe/3 in...

GHSA-855V-HQ7W-JMJW Open WebUI: Realtime endpoints accept Redis-revoked JWTs after signout/backchannel logout

Summary With Redis configured, Open WebUI supports JWT revocation: POST /api/v1/auths/signout per-token jti and OIDC back-channel logout per-user revokedat record revocations in Redis, and HTTP auth getcurrentuser rejects revoked tokens with 401. The realtime authentication surfaces do not perfor...

GHSA-GMFW-G93R-VG53 Open WebUI: Unauthenticated WebSocket Access to Collaborative Document Handlers (ydoc:awareness:update, ydoc:document:leave)

Summary The Socket.IO server is configured with alwaysconnect=True lines 78, 91 in backend/openwebui/socket/main.py and the connect handler line 329 never rejects unauthenticated connections. Two Ydoc event handlers have zero authentication checks, allowing unauthenticated clients to interact wit...

CVE-2026-65623 Quadratic CPU blow-up reassembling fragmented WebSocket messages in Bandit

Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversizemessage?/2 called from handleframe/3 in...

EUVD-2026-48718

Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversizemessage?/2 called from handleframe/3 in...

CVE-2026-65623

CVE-2026-65623 describes a Quadratic CPU blow-up in Bandit’s WebSocket message reassembly. The vulnerability arises when handling fragmented WebSocket frames: each non-final continuation frame is appended to a left-nested iolist and the entire buffer is re-measured with IO.iodata_length/1 on ever...

CVE-2026-65623 Quadratic CPU blow-up reassembling fragmented WebSocket messages in Bandit

Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversizemessage?/2 called from handleframe/3 in...

PT-2026-64373

Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly. The size guard 'Elixir.Bandit.WebSocket.Connection':oversize message?/2 called from handle frame/3 in...