AZL-94449 CVE-2026-54522 affecting package rubygem-msgpack for versions less than 1.8.4-1

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

UBUNTU-CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522

CVE-2026-54522 affects MessagePack for Ruby prior to 1.8.2, where MessagePack::Buffer#clear can leave internal rmem pointers stale after a chunk return, enabling a subsequent Buffer#write to alias the freed page and potentially disclose or corrupt cross-buffer data. Root cause: stale rmem_last/rm...

CVE-2026-54522 MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522 MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522 MessagePack::Buffer#clear Use-After-Free that Enables Cross-Buffer Disclosure

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54522

MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.2, MessagePack::Bufferclear in ext/msgpack/buffer.c leaves rmemlast, rmemend, and rmemowner stale after msgpackbuffershiftchunk returns an rmem page to the shared pool, allowing a subsequent...

CVE-2026-54620

A flaw was found in sqlite3-ruby, a Ruby binding for the SQLite3 embedded database. This vulnerability occurs because callbacks used for SQLite aggregate functions can be prematurely freed while still being referenced during aggregation. A local attacker could potentially exploit this...

GHSA-5P9G-J988-PCWV MCP Ruby SDK: Ruby SSE Session Poisoning

Summary Vulnerability: Missing Session Ownership Validation in the Ruby MCP SDK's Streamable and SSE HTTP transport implementation. Any attacker with a stolen session ID can execute tools with the victim's session. This is a silent attack - the victim's session is compromised and being used for...

EUVD-2026-50501

MCP Ruby SDK: Ruby SSE Session Poisoning...

MCP Ruby SDK: Ruby SSE Session Poisoning

Summary Vulnerability: Missing Session Ownership Validation in the Ruby MCP SDK's Streamable and SSE HTTP transport implementation. Any attacker with a stolen session ID can execute tools with the victim's session. This is a silent attack - the victim's session is compromised and being used for...

MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport

Summary An unauthenticated remote attacker can force any MCP Ruby SDK server using MCP::Server::Transports::StreamableHTTPTransport to allocate gigabytes of memory by sending a single oversized JSON-RPC POST. The transport reads the entire HTTP body into a Ruby String and parses it with...

EUVD-2026-50502

MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport...

EUVD-2026-50498

MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood...

EUVD-2026-50500

MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion DoS...

MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)

Summary The stdio transports in MCP::Server::Transports::StdioTransport and MCP::Client::Stdio read newline-delimited JSON-RPC frames using IOgets with no limit argument. CRuby's IOgets with no limit reads from the current position until the next separator \n with no upper bound on the returned...

GHSA-7683-3W9X-CH42 MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)

Summary The stdio transports in MCP::Server::Transports::StdioTransport and MCP::Client::Stdio read newline-delimited JSON-RPC frames using IOgets with no limit argument. CRuby's IOgets with no limit reads from the current position until the next separator \n with no upper bound on the returned...