Improper Handling of Length Parameter Inconsistency in Rack - CVE-2026-34831
Published: April 2, 2026
Vulnerability identifier: #VU124835
CSH Severity: Medium
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-34831
CWE-ID: CWE-130
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise the target system.
The vulnerability exists due to "Content-Length" mismatch in "Rack::Files" error responses. A remote attacker can cause response parsing inconsistencies or response desynchronization.
Affected software
Rack
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Real Time 15
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
Ubuntu
Public Cloud Module
Server Applications Module
openSUSE Leap
ruby-rack (Ubuntu package)
rmt-server-config
rmt-server-pubcloud
rmt-server
rmt-server-debuginfo
rmt-server-debugsource
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Real Time 15
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
Ubuntu
Public Cloud Module
Server Applications Module
openSUSE Leap
ruby-rack (Ubuntu package)
rmt-server-config
rmt-server-pubcloud
rmt-server
rmt-server-debuginfo
rmt-server-debugsource
How to mitigate CVE-2026-34831
Install updates from vendor's website.
Rack - addressed in versions 2.2.23, 3.1.21, 3.2.6
ruby-rack (Ubuntu package) - addressed in versions 1.5.2-3+deb8u3ubuntu1~esm11, 1.6.4-3ubuntu0.2+esm10, 1.6.4-4ubuntu0.2+esm10, 2.0.7-2ubuntu0.1+esm10, 2.1.4-5ubuntu1.2+esm3, 2.2.7-1ubuntu0.7, 3.1.16-0.1ubuntu0.3
rmt-server-config - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-pubcloud - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-debuginfo - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-debugsource - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
ruby-rack (Ubuntu package) - addressed in versions 1.5.2-3+deb8u3ubuntu1~esm11, 1.6.4-3ubuntu0.2+esm10, 1.6.4-4ubuntu0.2+esm10, 2.0.7-2ubuntu0.1+esm10, 2.1.4-5ubuntu1.2+esm3, 2.2.7-1ubuntu0.7, 3.1.16-0.1ubuntu0.3
rmt-server-config - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-pubcloud - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-debuginfo - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1
rmt-server-debugsource - addressed in versions 2.27-150400.3.54.1, 2.27-150500.3.47.1, 2.27-150700.3.20.1