CVE-2026-93475
Received Received - Intake

X.509 Parser Out-of-Bounds Write in NetX Secure

Vulnerability report for CVE-2026-93475, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: Eclipse Foundation

Description

The X.509 parser in NetX Secure accepts an RSA public key of any size, but every signature-verification path decrypts into fixed-size buffers dimensioned for the `NX_CRYPTO_MAX_RSA_MODULUS_SIZE` default of 4096 bits. A certificate carrying a larger modulus drives an out-of-bounds write past a file-scope static during ordinary certificate-chain verification. It is reachable pre-authentication. The issuer used for the crypto operation is looked up in the remote, peer-supplied store before the trusted store, so the attacker supplies the oversized key themselves as an intermediate in the chain they present. It triggers on a TLS or DTLS client verifying a malicious server's chain, and on a server performing client-certificate authentication.

CVSS Scores

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Meta Information

Published
2026-10-20
Last Modified
2026-10-20
Generated
2026-10-20
AI Q&A
2026-10-20
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Eclipse Foundation Eclipse ThreadX - NetX Duo 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-1284 The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

This is an out-of-bounds write vulnerability in NetX Secure X.509 affecting NetX Duo versions up to 6.5.1.202602. The X.509 parser accepts RSA public keys of any size but uses fixed-size buffers for 4096-bit keys. A certificate with a larger modulus causes an out-of-bounds write during chain verification. The flaw is exploitable pre-authentication by supplying an oversized key in a malicious certificate chain.

Detection Guidance

Check the version of NetX Duo in use. If it is 6.5.1.202602 or earlier, the system is vulnerable. Commands like 'grep' or 'find' can inspect library versions in installed packages or binaries.

Impact Analysis

An attacker can exploit this to corrupt adjacent memory in the .bss section, potentially leading to crashes, data corruption, or arbitrary code execution. No credentials or prior trust are required. It affects TLS/DTLS clients verifying server certificates and servers performing client-certificate authentication.

Mitigation Strategies

Upgrade NetX Duo to version 6.5.2.202603 or later. This patch adds bounds checks to reject oversized RSA keys during parsing and initialization.

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