Improper handling of highly compressed data in otp - CVE-2026-23943

Vulnerability identifier: #VU125773

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-23943

CWE-ID: CWE-409

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper handling of highly compressed data in ssh compression handling when decompressing crafted compressed packets. A remote attacker can send compressed packets that expand to excessive sizes when decompressed to cause a denial of service.

The zlib algorithm enables unauthenticated attacks after key exchange, while zlib@openssh.com enables attacks after authentication. When parallel_login=true, memory consumption can reach multiple gigabytes.

otp
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Real Time 15
Server Applications Module
openSUSE Leap
openEuler
erlang-edoc
erlang-inets
erlang-hipe
erlang-ftp
erlang-examples
erlang-eunit
erlang-et
erlang-erts
erlang-erl_interface
erlang-erl_docgen
erlang-eldap
erlang-xmerl
erlang-diameter
erlang-dialyzer
erlang-debugsource
erlang-debuginfo
erlang-debugger
erlang-crypto
erlang-compiler
erlang-common_test
erlang-asn1
erlang
erlang-kernel
erlang-wx
erlang-tools
erlang-tftp
erlang-syntax_tools
erlang-stdlib
erlang-ssl
erlang-ssh
erlang-snmp
erlang-sasl
erlang-reltool
erlang-public_key
erlang-parsetools
erlang-os_mon
erlang-odbc
erlang-observer
erlang-mnesia
erlang-megaco
erlang-jinterface
erlang-runtime_tools
erlang-doc
erlang-epmd-debuginfo
erlang-observer-src
erlang-diameter-src
erlang-reltool-src
erlang-jinterface-src
erlang-dialyzer-debuginfo
erlang-src
erlang-dialyzer-src
erlang-debugger-src
erlang-wx-debuginfo
erlang-et-src
erlang-epmd
erlang-wx-src
erlang26-reltool-src
erlang26-diameter-src
erlang26-et-src
erlang26-diameter
erlang26-observer-src
erlang26-debuginfo
erlang26-observer
erlang26-wx-src
erlang26-wx
erlang26
erlang26-jinterface
erlang26-epmd
erlang26-epmd-debuginfo
erlang26-doc
erlang26-debugsource
erlang26-debugger-src
erlang26-wx-debuginfo
erlang26-dialyzer-src
erlang26-reltool
erlang26-et
erlang26-debugger
erlang26-dialyzer
erlang26-src
erlang26-jinterface-src
erlang26-dialyzer-debuginfo

Install security update from vendor's website.

otp - addressed in versions 26.2.5.18, 27.3.4.9, 28.4.1
erlang-edoc - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-inets - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-hipe - update to 23.3.4.9-10
erlang-ftp - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-examples - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-eunit - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-et - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-erts - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-erl_interface - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-erl_docgen - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-eldap - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-xmerl - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-diameter - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-dialyzer - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-debugsource - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-debuginfo - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-debugger - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-crypto - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-compiler - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-common_test - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-asn1 - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-kernel - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-wx - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-tools - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-tftp - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-syntax_tools - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-stdlib - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-ssl - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-ssh - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-snmp - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-sasl - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-reltool - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-public_key - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-parsetools - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-os_mon - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-odbc - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-observer - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-mnesia - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-megaco - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-jinterface - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-runtime_tools - addressed in versions 23.3.4.9-10, 25.3.2.6-13
erlang-doc - update to 23.3.4.19-150300.3.32.1
erlang-epmd-debuginfo - update to 23.3.4.19-150300.3.32.1
erlang-observer-src - update to 23.3.4.19-150300.3.32.1
erlang-diameter - update to 23.3.4.19-150300.3.32.1
erlang-et - update to 23.3.4.19-150300.3.32.1
erlang-diameter-src - update to 23.3.4.19-150300.3.32.1
erlang-reltool-src - update to 23.3.4.19-150300.3.32.1
erlang-jinterface-src - update to 23.3.4.19-150300.3.32.1
erlang-dialyzer-debuginfo - update to 23.3.4.19-150300.3.32.1
erlang-jinterface - update to 23.3.4.19-150300.3.32.1
erlang-reltool - update to 23.3.4.19-150300.3.32.1
erlang-debugger - update to 23.3.4.19-150300.3.32.1
erlang-src - update to 23.3.4.19-150300.3.32.1
erlang-observer - update to 23.3.4.19-150300.3.32.1
erlang-debuginfo - update to 23.3.4.19-150300.3.32.1
erlang-dialyzer-src - update to 23.3.4.19-150300.3.32.1
erlang-debugger-src - update to 23.3.4.19-150300.3.32.1
erlang-dialyzer - update to 23.3.4.19-150300.3.32.1
erlang-debugsource - update to 23.3.4.19-150300.3.32.1
erlang - update to 23.3.4.19-150300.3.32.1
erlang-wx - update to 23.3.4.19-150300.3.32.1
erlang-wx-debuginfo - update to 23.3.4.19-150300.3.32.1
erlang-et-src - update to 23.3.4.19-150300.3.32.1
erlang-epmd - update to 23.3.4.19-150300.3.32.1
erlang-wx-src - update to 23.3.4.19-150300.3.32.1
erlang-src - update to 25.3.2.6-13
erlang26-reltool-src - update to 26.2.1-150300.7.25.1
erlang26-diameter-src - update to 26.2.1-150300.7.25.1
erlang26-et-src - update to 26.2.1-150300.7.25.1
erlang26-diameter - update to 26.2.1-150300.7.25.1
erlang26-observer-src - update to 26.2.1-150300.7.25.1
erlang26-debuginfo - update to 26.2.1-150300.7.25.1
erlang26-observer - update to 26.2.1-150300.7.25.1
erlang26-wx-src - update to 26.2.1-150300.7.25.1
erlang26-wx - update to 26.2.1-150300.7.25.1
erlang26 - update to 26.2.1-150300.7.25.1
erlang26-jinterface - update to 26.2.1-150300.7.25.1
erlang26-epmd - update to 26.2.1-150300.7.25.1
erlang26-epmd-debuginfo - update to 26.2.1-150300.7.25.1
erlang26-doc - update to 26.2.1-150300.7.25.1
erlang26-debugsource - update to 26.2.1-150300.7.25.1
erlang26-debugger-src - update to 26.2.1-150300.7.25.1
erlang26-wx-debuginfo - update to 26.2.1-150300.7.25.1
erlang26-dialyzer-src - update to 26.2.1-150300.7.25.1
erlang26-reltool - update to 26.2.1-150300.7.25.1
erlang26-et - update to 26.2.1-150300.7.25.1
erlang26-debugger - update to 26.2.1-150300.7.25.1
erlang26-dialyzer - update to 26.2.1-150300.7.25.1
erlang26-src - update to 26.2.1-150300.7.25.1
erlang26-jinterface-src - update to 26.2.1-150300.7.25.1
erlang26-dialyzer-debuginfo - update to 26.2.1-150300.7.25.1

• https://github.com/erlang/otp/security/advisories/GHSA-c836-qprm-jw9r
• https://github.com/advisories/GHSA-c836-qprm-jw9r

• Multiple vulnerabilities in otp
• openEuler 24.03 LTS SP1 update for erlang
• openEuler 24.03 LTS update for erlang
• openEuler 24.03 LTS SP3 update for erlang
• openEuler 24.03 LTS SP2 update for erlang
• SUSE update for erlang
• SUSE update for erlang26
• openEuler 22.03 LTS SP4 update for erlang