Bug 2496626 (CVE-2026-55952)

Summary: CVE-2026-55952 erlang: Erlang/OTP: Denial of Service in TLS 1.3 session ticket handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Erlang/OTP's SSL (Secure Sockets Layer) application. An unauthenticated remote attacker can send a specially crafted ClientHello message to a TLS 1.3 server with session tickets enabled. This can permanently disrupt the server's ability to handle session tickets, leading to a Denial of Service (DoS) for new TLS 1.3 connections until the SSL application is restarted. This vulnerability is caused by improper validation of PSK (Pre-Shared Key) identity and binder list lengths.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2496798, 2496799    
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Description OSIDB Bzimport 2026-07-02 17:02:20 UTC 
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 22.2 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 9.5 before 11.7.3, 11.6.0.3 and 11.2.12.10.