CVE-2026-34873

critical

Description

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.

References

https://www.helpnetsecurity.com/2026/09/14/debian-13-7-point-release/

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/

Details

Source: Mitre, NVD

Published: 2026-04-01

Updated: 2026-06-05

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

EPSS

EPSS: 0.00018