Is CVE-2026-34877 actively exploited?

CVE-2026-34877 has no public evidence of in-the-wild exploitation as of 2026-04-06.

What is the CVSS score for CVE-2026-34877?

CVE-2026-34877 has a CVSS score of 9.8 (CRITICAL severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

How do I patch CVE-2026-34877?

Patch guidance is available from arm security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-34877.

Which products are affected by CVE-2026-34877?

2 products: arm mbed tls, arm mbed tls.

Fix CVE-2026-34877 - CRITICAL arm mbed tls

Description

An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0. Insufficient protection of serialized SSL context or session structures allows an attacker who can modify the serialized structures to induce memory corruption, leading to arbitrary code execution. This is caused by Incorrect Use of Privileged APIs.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector: network
Complexity: low
Privileges: none
User Action: none
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high
Weaknesses: CWE-250 CWE-502 · Insecure Deserialization

Metadata

Primary Vendor: ARM
Published: 4/2/2026
Last Modified: 4/6/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-34877

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary