Denial-of-service (DoS)

org.apache.qpid, protonj2 is vulnerable to a denial-of-service DoS. The vulnerability is due to improper handling of the session flow-control incoming window, which allows an authenticated attacker to exceed the allowed window and potentially exhaust resources...

CLEANSTART-2026-ZS57953 authenticated attacker could exceed the session flow control incoming window potentially leading to denial of service

CVE-2026-66275 affects multiple packages. An authenticated attacker could exceed the session flow control incoming window potentially leading to denial of service. See references for individual vulnerability details...

DEBIAN-CVE-2026-85534

A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGSINITIALWINDOWSIZE while that buffered read is still in progres...

CVE-2026-85534 Libsoup: libsoup: http/2 client crash in on_data_source_read_callback when settings initial_window_size shrinks during deferred body read

A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGSINITIALWINDOWSIZE while that buffered read is still in progres...

CVE-2026-85534

A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGSINITIALWINDOWSIZE while that buffered read is still in progres...

CVE-2026-85534

A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGSINITIALWINDOWSIZE while that buffered read is still in progres...

CVE-2026-85534: Reachable Assertion

A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGSINITIALWINDOWSIZE while that buffered read is still in progres...

httpd: httpd: HTTP/2 Remote Denial of Service via compression bomb and Slowloris-style attack

A flaw was found in HTTP/2, affecting various web servers. A remote attacker can exploit this vulnerability by combining an HPACK compression bomb with a zero-byte flow-control window. This technique allows a small amount of data to expand into large memory allocations on the server, which are th...

PT-2026-67999

Name of the Vulnerable Software and Affected Versions Apache Qpid Proton-Dotnet versions prior to 1.1.0 Description An authenticated attacker could exceed the session flow control incoming window, which may result in a denial of service. This occurs when the system fails to properly manage the fl...

PT-2026-68003

Name of the Vulnerable Software and Affected Versions Apache Qpid ProtonJ2 versions prior to 1.2.0 Description An authenticated attacker could exceed the session flow control incoming window, which may result in a denial of service. Recommendations Upgrade to version 1.2.0...

CVE-2026-21714

A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOWUPDATE frames on stream 0 connection-level that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but the Http2Session object is never cleaned up. This vulnerabili...

HTTP/2: request for large response leads to denial of service

A vulnerability was found in HTTP/2. An attacker can open a HTTP/2 window so the peer can send without constraint. The TCP window remains closed so the peer cannot write the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the server's...

www/varnish7 -- Denial of Service

The Varnish Development Team reports: A denial of service attack can be performed on Varnish Cacher servers that have the HTTP/2 protocol turned on. An attacker can let the servers HTTP/2 connection control flow window run out of credits indefinitely and prevent progress in the processing of...