CVE-2026-54556 Http4s: HTTP/2 Denial of Service with Ember Backend

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala...

CVE-2026-54556

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala...

CVE-2026-54556 Http4s: HTTP/2 Denial of Service with Ember Backend

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala...

PT-2026-82110

Name of the Vulnerable Software and Affected Versions Http4s versions prior to 0.23.35 Http4s versions prior to 1.0.0-M47 Description An unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend when HTTP/2 is enabled. The issue resides in the Hpack wrapper...

libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability

This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of HTTP/2 HPACK path header. The issue results from the lack of proper...

PT-2026-81074

Name of the Vulnerable Software and Affected Versions libwebsockets affected versions not specified Description An issue exists in the parsing of the HTTP/2 HPACK path header due to insufficient validation of user-supplied data. This flaw can lead to an out-of-bounds write, where data is written...

python313-hpack-4.2.0-1.1 on GA media (moderate)

python313-hpack-4.2.0-1.1 on GA media Announcement ID: openSUSE-SU-2026:11556-1 Rating: moderate Cross-References: CVE-2016-6581 CVE-2026-59980 Affected Products: openSUSE Tumbleweed An update that solves 2 vulnerabilities can now be installed. Description: These are all security issues fixed in...

MiracleLinux 9 : haproxy-2.8.14-3.el9_8.2 (AXSA:2026-1627:03)

The remote MiracleLinux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the AXSA:2026-1627:03 advisory. haproxy: HAProxy: Denial of Service via HPACK dynamic table insertions CVE-2026-55204 haproxy: HAProxy: Response smuggling due to integer overflow i...

cowlib: Cowlib: Denial of Service due to unbounded HPACK/QPACK prefixed-integer decoding

A flaw was found in cowlib, an HTTP parser. An unauthenticated remote attacker could exploit this vulnerability by sending specially crafted HTTP/2 or HTTP/3 frames containing oversized HPACK or QPACK prefixed integers. This unbounded decoding process leads to excessive memory allocation and...

CVE-2026-75484 HTTP/2 header field values containing CR, LF or NUL are passed to the application unvalidated in Bandit

Improper Neutralization of CRLF Sequences 'CRLF Injection' vulnerability in mtrudel bandit allows an unauthenticated remote attacker to smuggle CR, LF, or NUL characters into application-visible request headers via HTTP/2. Bandit.HTTP2.Stream.readheaders/1 validates pseudo-header placement and...

CVE-2026-75484 HTTP/2 header field values containing CR, LF or NUL are passed to the application unvalidated in Bandit

Improper Neutralization of CRLF Sequences 'CRLF Injection' vulnerability in mtrudel bandit allows an unauthenticated remote attacker to smuggle CR, LF, or NUL characters into application-visible request headers via HTTP/2. Bandit.HTTP2.Stream.readheaders/1 validates pseudo-header placement and...

PT-2026-80604

These are all security issues fixed in the python313-hpack-4.2.0-1.1 package on the GA media of openSUSE Tumbleweed...

OPENSUSE-SU-2026:11556-1 python313-hpack-4.2.0-1.1 on GA media

These are all security issues fixed in the python313-hpack-4.2.0-1.1 package on the GA media of openSUSE Tumbleweed...

PT-2026-80780

Name of the Vulnerable Software and Affected Versions hpack versions prior to 4.2.0 Description Unbounded variable integer decoding can cause run-away computation when processing malformed input, resulting in On^2 runtime. This can effectively block further processing if the unsanitized input is...

MiracleLinux 8 : haproxy-1.8.27-5.el8_10.2 (AXSA:2026-1575:02)

The remote MiracleLinux 8 host has a package installed that is affected by a vulnerability as referenced in the AXSA:2026-1575:02 advisory. haproxy: HAProxy: Denial of Service via HPACK dynamic table insertions CVE-2026-55204 Tenable has extracted the preceding description block directly from the...

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...

haproxy security update

An update is available for haproxy. This update affects Rocky Linux 10. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for each vulnerability from the CVE list The haproxy packages provide a reliable, high-performance network load...

RLSA-2026:55679 Important: haproxy security update

The haproxy packages provide a reliable, high-performance network load balancer for TCP and HTTP-based applications. Security Fixes: haproxy: HAProxy: Denial of Service via HPACK dynamic table insertions CVE-2026-55204 haproxy: HAProxy: Response smuggling due to integer overflow in FastCGI record...

RLSA-2026:55772 Important: haproxy security update

The haproxy packages provide a reliable, high-performance network load balancer for TCP and HTTP-based applications. Security Fixes: haproxy: HAProxy: Denial of Service via HPACK dynamic table insertions CVE-2026-55204 haproxy: HAProxy: Response smuggling due to integer overflow in FastCGI record...

haproxy security update

An update is available for haproxy. This update affects Rocky Linux 9. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for each vulnerability from the CVE list The haproxy packages provide a reliable, high-performance network load balanc...