CVE-2026-34873

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-34873
An issue was discovered in Mbed TLS 3.5.0 through 4.0.0. Client impersonation can occur while resuming a TLS 1.3 session.

9.1 /10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
https://mbed-tls.readthedocs.io/en/latest/security-advisories/ Vendor Advisory
https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-client-impersonation-while-resuming-tls13-session/ Vendor Advisory
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
History

07 Apr 2026, 12:13

Type Values Removed Values Added
First Time Arm
Arm mbed Tls
CPE cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
References () https://mbed-tls.readthedocs.io/en/latest/security-advisories/ - () https://mbed-tls.readthedocs.io/en/latest/security-advisories/ - Vendor Advisory
References () https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-client-impersonation-while-resuming-tls13-session/ - () https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-client-impersonation-while-resuming-tls13-session/ - Vendor Advisory

02 Apr 2026, 17:16

Type Values Removed Values Added
CWE CWE-287
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 9.1

01 Apr 2026, 21:17

Type Values Removed Values Added
New CVE
Information

Published : 2026-04-01 21:17

Updated : 2026-04-07 12:13

NVD link : CVE-2026-34873

Mitre link : CVE-2026-34873

CVE.ORG link : CVE-2026-34873

JSON object : View

Products Affected

arm

  • mbed_tls
CWE
CWE-287

Improper Authentication