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Out of bound read and possible info leak in _nx_secure_tls_psk_identity_find()

Moderate
mrybczyn published GHSA-8h38-qjhh-mf2h Oct 15, 2025

Package

NetX Duo (Eclipse ThreadX)

Affected versions

<= 6.4.3

Patched versions

6.4.4

Description

The _nx_secure_tls_psk_identity_find() function is called to compare a psk identity string (that is extracted from a TLS hello client message) with identities that the TLS stack knows about. It loops over all the identities it knows about and performs a memcmp() for each stored identity, compared against the client hello provided identity. The length field used is the client hello provided length. There is no check to see if the client hello provided identity length is larger than the stored identity. If the client provided identity length is larger, an out of bound read could occur.

Given that memcmp() is used, and the length is controlled by a potential attacker, it could be used to brute force out of bound memory one byte at a time, causing an effective info leak. Should keys be stored in continuous memory, this issue could be used by an attack to recover keys.

It should be noted that there is a length check, however, the length check only occurs AFTER the call the memcmp().

code:

threadx\netxduo-master\nx_secure\src\nx_secure_tls_psk_identity_find.c

UINT _nx_secure_tls_psk_identity_find(NX_SECURE_TLS_SESSION *tls_session, UCHAR **psk_data, UINT *psk_length,

                                      UCHAR *psk_identity, UINT identity_length, UINT *psk_store_index)

{

UINT psk_list_size;

UINT compare_val;

UINT i;

...

    for (i = 0; i < psk_list_size; ++i)

    {

        /* Save off the PSK and its length. */

        compare_val = (UINT)NX_SECURE_MEMCMP(tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_id, psk_identity, identity_length); // <-- could read out of bound if psk_identity length > nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_id length

 

        /* See if the identity matched, and the length is the same (without the length, we could have a

           matching prefix which could be a possible attack vector... */

        if (compare_val == 0 && identity_length == tls_session -> nx_secure_tls_credentials.nx_secure_tls_psk_store[i].nx_secure_tls_psk_id_size)  // <-- this length check is too late. It should happen _BEFORE_ the memcmp

        {

...

        }

    }

...

}

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality Low
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVE ID

CVE-2025-55082

Weaknesses

Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer. Learn more on MITRE.

Credits