Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-1677— net: TLS 1.2 connections allowed on TLS 1.3 sockets

Quick assessment

Affected
zephyrproject-rtos Zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Zephyr是Zephyr开源的一个可扩展的实时操作系统 (RTOS)。 Zephyr存在安全漏洞，该漏洞源于使用IPPROTO_TLS_1_3创建的套接字在启用两种TLS版本时仍可协商TLS 1.2连接，因为套接字级别的协议选择未传播到mbedTLS，可能导致应用程序静默使用TLS 1.2并暴露于TLS 1.2特定弱点。

CVSS 5.3 · Medium EPSS 0.24% · P16

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject-rtos Zephyr *≤ 4.3 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-1677

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
net: TLS 1.2 connections allowed on TLS 1.3 sockets
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在会话协商时选择低安全性的算法(算法降级)
Source: CVE Program / CVE List V5
Vulnerability Title
Zephyr 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Zephyr是Zephyr开源的一个可扩展的实时操作系统 (RTOS)。 Zephyr存在安全漏洞，该漏洞源于使用IPPROTO_TLS_1_3创建的套接字在启用两种TLS版本时仍可协商TLS 1.2连接，因为套接字级别的协议选择未传播到mbedTLS，可能导致应用程序静默使用TLS 1.2并暴露于TLS 1.2特定弱点。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject-rtos Zephyr * ~ 4.3 -

II. Public POCs for CVE-2026-1677

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-1677

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-1677 (1)

IV. Related Vulnerabilities

Same product: Zephyr
Same vendor: zephyrproject-rtos
Same weakness: CWE-757

V. Comments for CVE-2026-1677

No comments yet

Leave a comment