{"affected":[{"ranges":[{"events":[{"introduced":"339a279f02ce38a7b23010e56000613e19abb21f"},{"fixed":"e77823e6d980b2ec0b4fe4ea3f2d098ca239e3ce"},{"fixed":"2c3e599797644310e5d4aa39c7193420e59dadff"},{"fixed":"9b5437c72fa3403a75c1aba28e5c532bc191c662"}],"repo":"https://github.com/erlang/otp","type":"GIT"}]}],"aliases":["GHSA-8c57-44c9-pc59","CVE-2026-55952"],"credits":[{"name":"Lukas Backström","type":"FINDER"},{"name":"Ingela Anderton Andin","type":"REMEDIATION_DEVELOPER"},{"name":"Dan Gudmundsson","type":"REMEDIATION_REVIEWER"},{"name":"Jakub Witczak","type":"REMEDIATION_REVIEWER"}],"database_specific":{"capec_ids":["CAPEC-153"],"cpe_ids":["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-1284"]},"details":"## Summary\n\nThe 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.\n\nAn 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.\n\nThis 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.\n\n## Workaround\n\n\\* Disable session tickets on TLS 1.3 servers by setting session\\_tickets to disabled in the server's ssl options.\n\\* Restrict the server to TLS 1.2 by setting versions to \\['tlsv1.2'\\] in the server's ssl options.\n\n## Configuration\n\nThe vulnerability only affects TLS 1.3 servers that have session tickets enabled (either stateful or stateless mode). TLS 1.2 connections and clients are not affected.","id":"EEF-CVE-2026-55952","modified":"2026-07-02T16:06:08.474Z","published":"2026-07-02T16:06:08.474Z","references":[{"type":"ADVISORY","url":"https://github.com/erlang/otp/security/advisories/GHSA-8c57-44c9-pc59"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-55952.html"},{"type":"WEB","url":"https://www.erlang.org/doc/system/versions.html#order-of-versions"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/e77823e6d980b2ec0b4fe4ea3f2d098ca239e3ce"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/2c3e599797644310e5d4aa39c7193420e59dadff"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/9b5437c72fa3403a75c1aba28e5c532bc191c662"}],"related":[],"schema_version":"1.7.3","severity":[{"score":"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","type":"CVSS_V4"}],"summary":"TLS 1.3 server denial of service via malformed ClientHello pre-shared key extension","upstream":[]}