Nonces should be used for the present occasion and only once.

What CVEs are caused by CWE-323?

39 recorded CVEs are attributed to CWE-323, including CVE-2025-59870, CVE-2017-7902, CVE-2026-59099.

How is CWE-323 detected?

Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

What are the consequences of CWE-323?

Exploiting CWE-323 can lead to: Bypass Protection Mechanism, Gain Privileges or Assume Identity.

Is CWE-323 actively exploited?

39 recorded CVEs are caused by CWE-323; none are currently in CISA's KEV catalog of actively exploited flaws.

CWE-323: Reusing a Nonce, Key Pair in Encryption

RadicalNotion.AI

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

This code takes a password, concatenates it with a nonce, then encrypts it before sending over a network:

Vulnerable example

void encryptAndSendPassword(char *password){

Because the nonce used is always the same, an attacker can impersonate a trusted party by intercepting and resending the encrypted password. This attack avoids the need to learn the unencrypted password.

This code sends a command to a remote server, using an encrypted password and nonce to prove the command is from a trusted party:

Vulnerable example

cpp

String command = new String("some command to execute");

Once again the nonce used is always the same. An attacker may be able to replay previous legitimate commands or execute new arbitrary commands.

CWE-323: Reusing a Nonce, Key Pair in Encryption

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Terminology & mappings

Mapped taxonomies

Frequently asked questions

References

Stay ahead of CWE-323

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Automated Static Analysis

Code examples

Illustrative examples

Related weaknesses

Parent

Terminology & mappings

Mapped taxonomies

Frequently asked questions

References

Stay ahead of CWE-323