Algorithm Downgrade in Erlang OTP - CVE-2026-55953

Vulnerability identifier: #VU146824

CSH Severity: High

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-55953

CWE-ID: CWE-757

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to read and modify data transmitted over the connection.

The vulnerability exists due to selection of a less-secure algorithm during negotiation in the OTP TLS/DTLS client cipher suite validation logic when processing a ServerHello message. A remote attacker can select an anonymous cipher suite that was not offered by the client to read and modify data transmitted over the connection.

This affects TLS versions up to 1.2 and all DTLS versions, while TLS-1.3 connections are not affected. The issue can bypass the client\'s verify_peer setting because anonymous cipher suites do not require a server certificate.

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

Install security update from vendor's website.

Erlang OTP - addressed in versions 17.0, 27.3.4.15, 28.5.0.4, 29.0.4
erlang-wx - update to 23.3.4.19-150300.3.39.1
erlang-epmd-debuginfo - update to 23.3.4.19-150300.3.39.1
erlang-debugsource - update to 23.3.4.19-150300.3.39.1
erlang - update to 23.3.4.19-150300.3.39.1
erlang-epmd - update to 23.3.4.19-150300.3.39.1
erlang-debuginfo - update to 23.3.4.19-150300.3.39.1
erlang-dialyzer - update to 23.3.4.19-150300.3.39.1
erlang-wx-debuginfo - update to 23.3.4.19-150300.3.39.1
erlang-debugger-src - update to 23.3.4.19-150300.3.39.1
erlang-diameter - update to 23.3.4.19-150300.3.39.1
erlang-et-src - update to 23.3.4.19-150300.3.39.1
erlang-dialyzer-debuginfo - update to 23.3.4.19-150300.3.39.1
erlang-et - update to 23.3.4.19-150300.3.39.1
erlang-reltool-src - update to 23.3.4.19-150300.3.39.1
erlang-reltool - update to 23.3.4.19-150300.3.39.1
erlang-observer - update to 23.3.4.19-150300.3.39.1
erlang-debugger - update to 23.3.4.19-150300.3.39.1
erlang-wx-src - update to 23.3.4.19-150300.3.39.1
erlang-dialyzer-src - update to 23.3.4.19-150300.3.39.1
erlang-jinterface - update to 23.3.4.19-150300.3.39.1
erlang-src - update to 23.3.4.19-150300.3.39.1
erlang-doc - update to 23.3.4.19-150300.3.39.1
erlang-diameter-src - update to 23.3.4.19-150300.3.39.1
erlang-jinterface-src - update to 23.3.4.19-150300.3.39.1
erlang-observer-src - update to 23.3.4.19-150300.3.39.1
erlang-compiler - update to 25.3.2.6-19
erlang-crypto - update to 25.3.2.6-19
erlang-debugger - update to 25.3.2.6-19
erlang-debuginfo - update to 25.3.2.6-19
erlang-debugsource - update to 25.3.2.6-19
erlang-dialyzer - update to 25.3.2.6-19
erlang-diameter - update to 25.3.2.6-19
erlang-edoc - update to 25.3.2.6-19
erlang-eldap - update to 25.3.2.6-19
erlang-erl_docgen - update to 25.3.2.6-19
erlang-erl_interface - update to 25.3.2.6-19
erlang-erts - update to 25.3.2.6-19
erlang-et - update to 25.3.2.6-19
erlang-asn1 - update to 25.3.2.6-19
erlang - update to 25.3.2.6-19
erlang-xmerl - update to 25.3.2.6-19
erlang-wx - update to 25.3.2.6-19
erlang-tools - update to 25.3.2.6-19
erlang-tftp - update to 25.3.2.6-19
erlang-syntax_tools - update to 25.3.2.6-19
erlang-stdlib - update to 25.3.2.6-19
erlang-ssl - update to 25.3.2.6-19
erlang-ssh - update to 25.3.2.6-19
erlang-src - update to 25.3.2.6-19
erlang-common_test - update to 25.3.2.6-19
erlang-snmp - update to 25.3.2.6-19
erlang-reltool - update to 25.3.2.6-19
erlang-sasl - update to 25.3.2.6-19
erlang-runtime_tools - update to 25.3.2.6-19
erlang-eunit - update to 25.3.2.6-19
erlang-public_key - update to 25.3.2.6-19
erlang-parsetools - update to 25.3.2.6-19
erlang-os_mon - update to 25.3.2.6-19
erlang-odbc - update to 25.3.2.6-19
erlang-observer - update to 25.3.2.6-19
erlang-mnesia - update to 25.3.2.6-19
erlang-megaco - update to 25.3.2.6-19
erlang-kernel - update to 25.3.2.6-19
erlang-jinterface - update to 25.3.2.6-19
erlang-inets - update to 25.3.2.6-19
erlang-ftp - update to 25.3.2.6-19
erlang-examples - update to 25.3.2.6-19
erlang26-src - update to 26.2.1-150300.7.28.1
erlang26-et-src - update to 26.2.1-150300.7.28.1
erlang26 - update to 26.2.1-150300.7.28.1
erlang26-epmd - update to 26.2.1-150300.7.28.1
erlang26-jinterface - update to 26.2.1-150300.7.28.1
erlang26-wx-src - update to 26.2.1-150300.7.28.1
erlang26-dialyzer-src - update to 26.2.1-150300.7.28.1
erlang26-diameter-src - update to 26.2.1-150300.7.28.1
erlang26-wx - update to 26.2.1-150300.7.28.1
erlang26-et - update to 26.2.1-150300.7.28.1
erlang26-debugger - update to 26.2.1-150300.7.28.1
erlang26-reltool-src - update to 26.2.1-150300.7.28.1
erlang26-reltool - update to 26.2.1-150300.7.28.1
erlang26-debugger-src - update to 26.2.1-150300.7.28.1
erlang26-dialyzer-debuginfo - update to 26.2.1-150300.7.28.1
erlang26-debugsource - update to 26.2.1-150300.7.28.1
erlang26-epmd-debuginfo - update to 26.2.1-150300.7.28.1
erlang26-doc - update to 26.2.1-150300.7.28.1
erlang26-diameter - update to 26.2.1-150300.7.28.1
erlang26-wx-debuginfo - update to 26.2.1-150300.7.28.1
erlang26-observer-src - update to 26.2.1-150300.7.28.1
erlang26-debuginfo - update to 26.2.1-150300.7.28.1
erlang26-observer - update to 26.2.1-150300.7.28.1
erlang26-dialyzer - update to 26.2.1-150300.7.28.1
erlang26-jinterface-src - update to 26.2.1-150300.7.28.1
erlang - addressed in versions 26.2.5.21-5.fc43, 26.2.5.21-5.fc44
erlang (Debian package) - update to 1:27.3.4.1+dfsg-1+deb13u3

• https://github.com/erlang/otp/security/advisories/GHSA-c6cw-pr89-w882

• Debian update for erlang
• Fedora 44 update for erlang
• Fedora 43 update for erlang
• openEuler 24.03 LTS SP4 update for erlang
• Multiple vulnerabilities in Erlang OTP
• openEuler 24.03 LTS SP3 update for erlang
• openEuler 24.03 LTS SP1 update for erlang
• SUSE update for erlang26
• SUSE update for erlang