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Fencer Vulns
high 8.2

CVE-2026-94200 json

TLS 1.3 client ticket store crashed by NewSessionTicket with empty early_data extension in ssl

published 2026-10-14 25 d ago modified 2026-10-16 23 d ago also EUVD-2026-101384

cvss
8.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Improper Validation of Consistency within Input vulnerability in Erlang OTP ssl (tls_handshake_1_3, ssl_handshake and tls_client_ticket_store modules) allows a malicious TLS 1.3 server to cause a denial of service of the ssl application on the client node.

The TLS 1.3 client decodes the extensions of a NewSessionTicket message as if they came from EncryptedExtensions. It therefore accepts a 0-length early_data extension, a form that is only valid in ClientHello and EncryptedExtensions. With {session_tickets, auto}, the client stores the ticket in the node-global tls_client_ticket_store. On the next automatic resumption, tls_handshake_1_3:get_max_early_data/1 crashes the store with a case_clause. Repeated crashes can exceed the restart intensity of the ssl supervisors, which use the rest_for_one strategy, and take down ssl for all connections on the node.

This issue affects OTP from OTP 23.3 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to ssl from 10.3 before 11.2.12.14, 11.6.0.7, and 11.7.8.

Patch / fix

  • Erlang OTP 11.2.12.14, 11.6.0.7, 11.7.8, 27.3.4.19, 28.5.0.8, 29.1.2
  • erlang Debian 14 1:29.1.2+dfsg-1

debian advisories DEBIAN-CVE-2026-94200

  • erlang27 hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-et hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-wx hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-ftp hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-ssh hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-ssl hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-asn1 hummingbird 1 27.3.4.19-0.1.hum1
  • erlang27-edoc hummingbird 1 27.3.4.19-0.1.hum1

red hat advisories RHSA-2026:83217

  • erlang Azure Linux 3.0 26.2.5.21-8

azure linux advisories AZL-108204

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-94200 updated cvss 5.9

erlang: Erlang: Denial of Service via malformed TLS 1.3 session ticket

  • Red Hat OpenStack Platform 16.2 erlang, erlang-ssl, erlang-asn1, erlang-erts, erlang-hipe, erlang-sasl, +15 more Red Hat OpenStack Platform 17.1 erlang, erlang-ssl, erlang-asn1, erlang-erts, erlang-sasl, erlang-snmp, +14 more Red Hat OpenStack Platform 18.0 erlang
    affected: workaround, no fix available “Disable automatic TLS session tickets on client connections by setting session_tickets => manual or session_tickets => disabled in the client SSL socket options.”
  • Red Hat Hardened Images erlang27 27.3.4.19-0.1.hum1, erlang27-et 27.3.4.19-0.1.hum1, erlang27-wx 27.3.4.19-0.1.hum1, erlang27-ftp 27.3.4.19-0.1.hum1, erlang27-ssh 27.3.4.19-0.1.hum1, erlang27-ssl 27.3.4.19-0.1.hum1, +33 more
    fixed: vendor fix “Disable automatic TLS session tickets on client connections by setting session_tickets => manual or session_tickets => disabled in the client SSL socket options.” RHSA-2026:83217
  • Red Hat OpenStack Platform 13 (Queens) erlang, erlang-ic, erlang-ftp, erlang-ose, erlang-ssh, erlang-ssl, +36 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • Erlang OTP

Classification

Weakness
  • CWE-1288 Improper Validation of Consistency within Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.