{"cve":"CVE-2026-1677","nvd":{"published":"2026-05-11T06:16:08.683","modified":"2026-10-15T23:17:36.037","status":"Analyzed","description":"Zephyr sockets created with `IPPROTO_TLS_1_3` can still negotiate a TLS 1.2 connection when both TLS versions are enabled in Kconfig, because the socket-level protocol selection is not propagated to mbedTLS (e.g. via `mbedtls_ssl_conf_min_tls_version`). The ClientHello advertises both versions and the peer can establish TLS 1.2, so applications that assumed `IPPROTO_TLS_1_3` enforces TLS 1.3 may silently use TLS 1.2 and remain exposed to TLS 1.2-specific weaknesses. As a workaround, the `TLS_CIPHERSUITE_LIST` socket option can be restricted to TLS 1.3-only cipher suites.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-757"],"references":["https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq"],"products":["zephyrproject:zephyr"],"source":"nvd","synced_at":"2026-10-19T22:33:55.586217763+00:00"},"epss":{"cve":"CVE-2026-1677","score":0.00243,"percentile":0.15384,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}