HTTP Request Smuggling

Overview Affected versions of this package are vulnerable to HTTP Request Smuggling in the HTTP/1.1 parsing process. An attacker can bypass front-end controls, capture another user's headers, or poison a cache by sending requests with differing duplicate Content-Length headers, especially when th...

HTTP Request Smuggling

Overview Affected versions of this package are vulnerable to HTTP Request Smuggling in the HTTP/1.1 parsing process. An attacker can bypass front-end controls, capture another user's headers, or poison a cache by sending requests with differing duplicate Content-Length headers, especially when th...

HTTP Request Smuggling

Overview Affected versions of this package are vulnerable to HTTP Request Smuggling in the HTTP/1.1 parsing process. An attacker can bypass front-end controls, capture another user's headers, or poison a cache by sending requests with differing duplicate Content-Length headers, especially when th...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS due to the lack of enforcement of SETTINGSMAXCONCURRENTSTREAMS in HTTP/2 connections. Details Denial of Service DoS describes a family of attacks, all aimed at making a system inaccessible to its intended and...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS due to the lack of enforcement of SETTINGSMAXCONCURRENTSTREAMS in HTTP/2 connections. Details Denial of Service DoS describes a family of attacks, all aimed at making a system inaccessible to its intended and...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS due to the lack of enforcement of SETTINGSMAXCONCURRENTSTREAMS in HTTP/2 connections. Details Denial of Service DoS describes a family of attacks, all aimed at making a system inaccessible to its intended and...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS in the HTTP/2 flow-control process. An attacker can exhaust system memory by sending data faster than it is consumed by the application, causing unbounded buffering and potential service disruption. Details Denial ...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS in the HTTP/2 flow-control process. An attacker can exhaust system memory by sending data faster than it is consumed by the application, causing unbounded buffering and potential service disruption. Details Denial ...

Denial of Service (DoS)

Overview Affected versions of this package are vulnerable to Denial of Service DoS in the HTTP/2 flow-control process. An attacker can exhaust system memory by sending data faster than it is consumed by the application, causing unbounded buffering and potential service disruption. Details Denial ...

Allocation of Resources Without Limits or Throttling

Overview Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the H2Connection process. An attacker can exhaust heap memory and cause service disruption by sending HTTP/2 HEADERS or PUSHPROMISE frames without ENDHEADERS, followed by unbounded...

Allocation of Resources Without Limits or Throttling

Overview Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the H2Connection process. An attacker can exhaust heap memory and cause service disruption by sending HTTP/2 HEADERS or PUSHPROMISE frames without ENDHEADERS, followed by unbounded...

CVE-2026-88975

Http4s is a Scala interface for HTTP services. Prior to 0.23.37 and 1.0.0-M48, Ember’s HTTP/2 read loop parses a frame’s 24-bit declared length but waits to buffer the entire payload before comparing it with SETTINGSMAXFRAMESIZE. An unauthenticated peer can declare a payload near 16 MiB on a...

CVE-2026-69217

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive intermediary that selects a different...

CVE-2026-69218

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, When Ember receives an HTTP/2 HEADERS or PUSHPROMISE frame without ENDHEADERS, H2Connection buffers the header block and subsequent CONTINUATION fragments without a size bound. A remote peer can keep an incomplete bloc...

CVE-2026-69203

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, An Ember server with HTTP/2 enabled through withHttp2 does not enforce SETTINGSMAXCONCURRENTSTREAMS for peer-created streams. One unauthenticated connection can open an unbounded number of streams, each retaining...

CVE-2026-69202

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/2 flow-control window is replenished according to bytes received from the network rather than bytes consumed by the application, while each stream stores DATA in an unbounded channel. A hostile peer can...

GHSA-GQ9P-F254-H286 Http4s: Ember HTTP/2 buffers a frame's declared payload before checking SETTINGS_MAX_FRAME_SIZE

Summary An unauthenticated peer can make Ember's HTTP/2 read loop hold 16 MiB of a single frame in memory on a connection where Ember advertised a 16 KiB limit. The declared length is readable from the frame's first 9 bytes, but it is not compared against SETTINGSMAXFRAMESIZE until the whole...

Http4s: Ember HTTP/2 buffers a frame's declared payload before checking SETTINGS_MAX_FRAME_SIZE

Summary An unauthenticated peer can make Ember's HTTP/2 read loop hold 16 MiB of a single frame in memory on a connection where Ember advertised a 16 KiB limit. The declared length is readable from the frame's first 9 bytes, but it is not compared against SETTINGSMAXFRAMESIZE until the whole...

GHSA-CP4Q-FQW9-4HF6 Http4s Ember HTTP/2: unbounded continuation frame accumulation

When Ember receives an HTTP/2 HEADERS or PUSHPROMISE frame without the ENDHEADERS flag, it buffers the header block fragment and waits for subsequent CONTINUATION frames. These accumulate unbounded until the connection closes. Impact A remote, unauthenticated peer can exhaust the heap on any Embe...

Http4s Ember HTTP/2: unbounded continuation frame accumulation

When Ember receives an HTTP/2 HEADERS or PUSHPROMISE frame without the ENDHEADERS flag, it buffers the header block fragment and waits for subsequent CONTINUATION frames. These accumulate unbounded until the connection closes. Impact A remote, unauthenticated peer can exhaust the heap on any Embe...