CVE-2026-55952 TLS 1.3 server denial of service via malformed ClientHello pre-shared key extension
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-55952?
CVE-2026-55952 is a high-severity vulnerability in Erlang OTP, published on 2 Jul 2026.
Official 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 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssl from 9.5 before 11.7.3, 11.6.0.3 and 11.2.12.10.
Weakness: CWE-1284
Which versions are affected by CVE-2026-55952?
It affects 2 products.
Products include Erlang Erlang\/Otp, Erlang Erlang\/Ssl.
How do I fix CVE-2026-55952?
Upgrade to a fixed version.
Is CVE-2026-55952 being exploited?
There is no known exploitation of CVE-2026-55952 in the wild and no public exploit code.
Other vulnerabilities in Erlang OTP
- CVE-2022-37026 Auth bypass in n/a
- CVE-2016-10253 Memory corruption in n/a
- CVE-2026-55953 TLS 1.2 and DTLS client accepts unoffered anonymous cipher suite, bypassing server authentication
- CVE-2026-49759 Stack buffer overflow in SCTP error cause parsing in inet_drv allows remote VM crash
- CVE-2026-58227 TLS/DTLS denial of service via unbounded recursion on cross-signed peer certificate chain
Sources
Also known as DEBIAN-CVE-2026-55952, EEF-CVE-2026-55952, GHSA-8c57-44c9-pc59, UBUNTU-CVE-2026-55952.