CVE-2026-1677
net: TLS 1.2 connections allowed on TLS 1.3 sockets
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.
INFO
Published Date :
May 11, 2026, 6:16 a.m.
Last Modified :
Oct. 26, 2026, 6:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-1677
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | e2e69745-5e70-4e92-8431-deb5529a81ad | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Propagate socket-level protocol selection to mbedTLS.
- Configure mbedTLS to enforce TLS 1.3 minimum version.
- Restrict TLS cipher suites to TLS 1.3 only.
- Update Zephyr sockets to enforce TLS 1.3.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-1677.
| URL | Resource |
|---|---|
| https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq | Exploit Mitigation Patch Vendor Advisory |
| https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq | Exploit Mitigation Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-1677 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-1677
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-1677 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-1677 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: Zephyr de zephyrproject-rtos, Description: Los sockets de Zephyr creados con “IPPROTO_TLS_1_3” aún pueden negociar una conexión TLS 1.2 cuando ambas versiones de TLS están habilitadas en Kconfig, porque la selección de protocolo a nivel de socket no se propaga a mbedTLS (por ejemplo, a través de “mbedtls_ssl_conf_min_tls_version”). El ClientHello anuncia ambas versiones y el par puede establecer TLS 1.2, por lo que las aplicaciones que asumieron que “IPPROTO_TLS_1_3” impone TLS 1.3 pueden usar silenciosamente TLS 1.2 y permanecer expuestas a debilidades específicas de TLS 1.2. Como solución alternativa, la opción de socket “TLS_CIPHERSUITE_LIST” puede restringirse a suites de cifrado solo de TLS 1.3. -
CVE Modified by [email protected]
Oct. 15, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/1xxx/CVE-2026-1677.json">CVE-2026-1677</a> Added Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Removed Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Removed Reference Type https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Types: Exploit, Mitigation, Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Oct. 15, 2026
Action Type Old Value New Value Added Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Removed Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Removed Reference Type https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Types: Exploit, Mitigation, Patch, Vendor Advisory -
Initial Analysis by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:* versions up to (including) 4.3.0 Added Reference Type Zephyr Project: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Types: Exploit, Mitigation, Patch, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq Types: Exploit, Mitigation, Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-1677', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-11T16:31:12.694213Z'} -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/zephyrproject-rtos/zephyr', 'vendor': 'zephyrproject-rtos', 'product': 'Zephyr', 'versions': [{'status': 'affected', 'version': '*', 'versionType': 'git', 'lessThanOrEqual': '4.3'}], 'packageName': 'Zephyr', 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 11, 2026
Action Type Old Value New Value Added Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq -
New CVE Received by [email protected]
May. 11, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-757 Added Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-23r2-m5wx-4rvq