CVE-2026-69202

Http4s is a Scala HTTP services library. In versions prior to 0.23.35 and 1.0.0-M47 , Ember's HTTP/2 flow-control window is replenished based on bytes received from the network rather than bytes consumed by the application, and each stream stores DATA in an unbounded channel . A remote peer can t...

CVE-2026-69218 Http4s Ember HTTP/2: unbounded continuation frame accumulation

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-2026-69218

Http4s Ember HTTP/2 is vulnerable to unbounded continuation frame accumulation in its H2Connection component. When Ember receives an HTTP/2 HEADERS or PUSH_PROMISE frame without END_HEADERS, it buffers the header block and subsequent CONTINUATION fragments without a size bound . A remote peer can...

CVE-2026-69218 Http4s Ember HTTP/2: unbounded continuation frame accumulation

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-2026-69218 Http4s Ember HTTP/2: unbounded continuation frame accumulation

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...

EUVD-2026-79195

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...

EUVD-2026-79194

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-2026-69203

Http4s is a Scala HTTP service library. Prior to versions 0.23.35 and 1.0.0-M47 , its Ember server with HTTP/2 enabled via withHttp2 does not enforce SETTINGS_MAX_CONCURRENT_STREAMS for peer-created streams. A single unauthenticated connection can open an unbounded number of streams, each retaini...

CVE-2026-69203 Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS

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-2026-69203 Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS

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-2026-69203 Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS

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-2026-69217 Http4s: Ember Server accepts duplicate Content-Length headers

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-2026-69217 Http4s: Ember Server accepts duplicate Content-Length headers

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-2026-69217

Http4s (a Scala HTTP service interface) is vulnerable to CL.CL request smuggling due to its Ember HTTP/1.1 parser accepting differing duplicate Content-Length headers and using the last value instead of rejecting the message. Affected versions are prior to 0.23.35 and 1.0.0-M47 . When an Ember se...

EUVD-2026-79193

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-2026-69217 Http4s: Ember Server accepts duplicate Content-Length headers

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-2026-69210 Http4s: WebSocket decoder accepts negative length, causing infinite decode loop

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAXVALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handshake through an Ember server can send su...

CVE-2026-69210

Http4s , a Scala HTTP service library, is vulnerable to a denial of service via its WebSocket decoder. In versions prior to 0.23.35 and 1.0.0-M47 , FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but incorrectly permits negative 64-bit lengths . A remote client...

CVE-2026-69216

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data...

CVE-2026-69213

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/2 serializes outbound frames through one unbounded queue consumed by writeLoop. When the peer stops reading, an unauthenticated HTTP/2 client can continue sending PING, SETTINGS, or DATA frames that cause...