CVE-2026-73493

Http4s http4s-blaze-server is a minimal, idiomatic Scala interface for HTTP services. Prior to 0.23.18 and 1.0.0-M42, http4s-blaze-server aggregates 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...

CVE-2026-73493

Summary: The CVE affects http4s-blaze-server in WebSocket handling where fragmented messages can be aggregated without an upper bound, causing unbounded heap growth and potential DoS via OutOfMemoryError on the Blaze server thread. Affected scope: any http4s application serving WebSocket routes o...

CVE-2026-73493 http4s-blaze-server: Unbounded WebSocket message aggregation

Http4s http4s-blaze-server is a minimal, idiomatic Scala interface for HTTP services. Prior to 0.23.18 and 1.0.0-M42, http4s-blaze-server aggregates 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...

PT-2026-71347

Name of the Vulnerable Software and Affected Versions http4s-blaze-server versions prior to 0.23.18 http4s-blaze-server versions prior to 1.0.0-M42 Description The software aggregates fragments of incoming WebSocket messages without limiting the total size or the number of fragments. A client can...

Allocation of Resources Without Limits or Throttling

Overview Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling through the aggregation of incoming WebSocket message fragments without any limit on total size or fragment count. An attacker can exhaust server memory and cause a denial of service ...

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...

HTTP Request Smuggling

Overview Affected versions of this package are vulnerable to HTTP Request Smuggling in the process that merges HTTP/1.1 chunked-body trailer fields into Request.headers. An attacker can inject arbitrary HTTP headers by sending specially crafted trailer fields, potentially bypassing header-based...

CVE-2021-21293

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection acceptance leads to file handle exhaustion. Blaze, accepts connections unconditionally on a...

Design/Logic Flaw

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection acceptance leads to file handle exhaustion. Blaze, accepts connections unconditionally on a...

Unbounded connection acceptance leads to file handle exhaustion

Impact All servers running blaze-core = 0.14.14, including blaze-http and http4s-blaze-server users, are affected. Blaze, accepts connections unconditionally on a dedicated thread pool. This has the net effect of amplifying degradation in services that are unable to handle their current request...

GHSA-XMW9-Q7X9-J5QC Unbounded connection acceptance leads to file handle exhaustion

Impact All servers running blaze-core = 0.14.14, including blaze-http and http4s-blaze-server users, are affected. Blaze, accepts connections unconditionally on a dedicated thread pool. This has the net effect of amplifying degradation in services that are unable to handle their current request...

CVE-2021-21293 Unbounded connection acceptance leads to file handle exhaustion

blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection acceptance leads to file handle exhaustion. Blaze, accepts connections unconditionally on a...

PT-2021-14395 · Unknown +1 · Blaze-Core +5

Name of the Vulnerable Software and Affected Versions: blaze-core versions prior to 0.14.15 http4s-blaze-server versions prior to 0.21.17 Description: The issue is caused by unbounded connection acceptance in blaze-core, leading to file handle exhaustion. This can amplify degradation in services...

Http4s Blaze Resource Management Error Vulnerability

Http4s Blaze is a java-based NIO codebase for processing network streams from the Http4s organization. A security vulnerability exists in Http4s Blaze that originates from accepting connections without restriction on a selector pool. The following products and versions are affected: Http4s before...

Http4s Blaze Resource Management Error Vulnerability

Http4s Blaze is a java-based NIO codebase for processing network streams from the Http4s organization. A resource management error vulnerability exists in Http4s Blaze that stems from the fact that unlimited connection acceptance will result in file handle exhaustion...