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Vulnerability record · CVE-2026-34877 · published 2 April 2026

CVE-2026-34877: Arm mbed tls execution with unnecessary privileges vulnerability

Arm · Mbed Tls

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.

9.8 CVSS 3.1 Critical EPSS 0.73% · top 47.8% CWE-250 · Execution with unnecessary privilegesCWE-502 · Deserialization of untrusted data
9.8CVSS 3.1 base score
0.73%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
24 Jul 2026Last modified by NVD

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

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
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-serialized-data/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-34875Trustedfirmware mbed tls classic buffer overflow vulnerabilityAn issue was discovered in Mbed TLS through 3.6.5 and TF-PSA-Crypto 1.0.0. A buffer overflow can occur in public key export for FFDH keys.EPSS 0.60%9.8CVE-2025-47917Arm mbed tls use after free vulnerabilityMbed TLS before 3.6.4 allows a use-after-free in certain situations of applications that are developed in accordance with the documentation. The func…EPSS 2.1%9.8CVE-2024-49195Trustedfirmware mbed tls out-of-bounds write vulnerabilityMbed TLS 3.5.x through 3.6.x before 3.6.2 has a buffer underrun in pkwrite when writing an opaque key pairEPSS 0.63%9.8CVE-2024-45158Trustedfirmware mbed tls stack-based buffer overflow vulnerabilityAn issue was discovered in Mbed TLS 3.6 before 3.6.1. A stack buffer overflow in mbedtls_ecdsa_der_to_raw() and mbedtls_ecdsa_raw_to_der() can occur …EPSS 0.68%9.8CVE-2024-45159Trustedfirmware mbed tls improper certificate validation vulnerabilityAn issue was discovered in Mbed TLS 3.x before 3.6.1. With TLS 1.3, when a server enables optional authentication of the client, if the client-provid…EPSS 0.39%9.8CVE-2023-45199Trustedfirmware mbed tls classic buffer overflow vulnerabilityMbed TLS 3.2.x through 3.4.x before 3.5 has a Buffer Overflow that can lead to remote Code execution.EPSS 1.1%9.8CVE-2022-46393Arm mbed tls out-of-bounds read vulnerabilityAn issue was discovered in Mbed TLS before 2.28.2 and 3.x before 3.3.0. There is a potential heap-based buffer overflow and heap-based buffer over-re…EPSS 1.2%9.8CVE-2021-44732Arm mbed tls double free vulnerabilityMbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure.EPSS 2.6%

Source: NIST National Vulnerability Database (record CVE-2026-34877), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.