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OpenAdvisories
High · 8.2 CVE-2026-55952 EUVD-2026-41412

TLS 1.3 server denial of service via malformed ClientHello pre-shared key extension

Published Jul 2, 2026 · Updated Nov 11, 2026 · Assigned by EEF

Description

The Erlang/OTP ssl application does not validate that the PSK identity list and binder list carried in a TLS 1.3 ClientHello pre-shared key extension have equal length before passing them to the session ticket handler. In tls_handshake_1_3:handle_pre_shared_key/3, an OfferedPreSharedKeys record with a mismatched number of identities and binders is forwarded directly to tls_server_session_ticket:use/4, which crashes the session ticket handler process.

An unauthenticated remote attacker can send a single crafted ClientHello to a TLS 1.3 server with session tickets enabled (stateful or stateless mode) and permanently disrupt session ticket handling on that listener. New TLS 1.3 handshakes complete but subsequently crash when the server attempts to issue a session ticket, effectively making TLS 1.3 unusable on the affected listener until the ssl application is restarted. TLS 1.2 connections are not affected.

This issue affects OTP from OTP 22.2 before OTP 27.3.4.14, OTP 28.5.0.3, and OTP 29.0.3, corresponding to ssl from 9.5 before 11.2.12.10, 11.6.0.3, and 11.7.3.

Affected products

VendorProductAffectedFixed
Erlang OTP 22.2, 9.5 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 erlang 1:29.0.3+dfsg-1 —
Debian 13 erlang 1:27.3.4.1+dfsg-1+deb13u3 —
Debian 12 erlang No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS erlang 1:27.3.4.6+dfsg-1ubuntu0.2 USN-8901-1
Ubuntu 25.10 erlang No fix yet —
Ubuntu 24.04 LTS erlang 1:25.3.2.8+dfsg-1ubuntu4.8 USN-8901-1
Ubuntu 22.04 LTS erlang 1:24.2.1+dfsg-1ubuntu0.8 USN-8901-1
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 20.04 LTS erlang 1:22.2.7+dfsg-1ubuntu0.5+esm3 USN-8901-1
Ubuntu Pro 18.04 LTS erlang 1:20.2.2+dfsg-1ubuntu2+esm4 USN-8901-1
Ubuntu Pro 16.04 LTS erlang 1:18.3-dfsg-1ubuntu3.1+esm4 USN-8901-1
Ubuntu Pro 14.04 LTS erlang 1:16.b.3-dfsg-1ubuntu2.2+esm3 USN-8901-1
ReleasePackageFixed inAdvisory
Red Hat Hardened Images 1 erlang27 +38 27.3.4.17-1.hum1 RHSA-2026:63160
ReleasePackageFixed inAdvisory
SLES 15 SP7 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLES 15 SP7 erlang26 26.2.1-150300.7.28.1 SUSE-SU-2026:3579-1
SLES 15 SP6 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLES 15 SP6 erlang26 26.2.1-150300.7.28.1 SUSE-SU-2026:3579-1
SLES 15 SP5 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLES 15 SP4 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP6 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLES for SAP 15 SP6 erlang26 26.2.1-150300.7.28.1 SUSE-SU-2026:3579-1
SLES for SAP 15 SP5 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLES for SAP 15 SP4 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLE HPC 15 SP5 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
SLE HPC 15 SP4 erlang 23.3.4.19-150300.3.39.1 SUSE-SU-2026:3645-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed erlang 28.5.0.4-1.1 openSUSE-SU-2026:11559-1
openSUSE Tumbleweed erlang27 27.1.3-3.1 openSUSE-SU-2026:11560-1

Advisories 9

References