CVE-2026-1677

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.
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 - () 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')