Is CVE-2026-34873 actively exploited?

CVE-2026-34873 has no public evidence of in-the-wild exploitation as of 2026-04-07.

What is the CVSS score for CVE-2026-34873?

CVE-2026-34873 has a CVSS score of 9.1 (CRITICAL severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Patch guidance is available from arm security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-34873.

2 products: arm mbed tls, arm mbed tls.

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.

Primary Vendor: ARM
Published: 4/1/2026
Last Modified: 4/7/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.