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.
References
Configurations
No configuration.
History
11 May 2026, 18:16
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq - |
11 May 2026, 06:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-11 06:16
Updated : 2026-05-13 15:25
NVD link : CVE-2026-1677
Mitre link : CVE-2026-1677
CVE.ORG link : CVE-2026-1677
JSON object : View
Products Affected
No product.
CWE
CWE-757
Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
