CWE-1038 Class Draft Low likelihood

Insecure Automated Optimizations

This vulnerability occurs when software uses automated tools to optimize code for performance or efficiency, but those optimizations accidentally weaken or bypass critical security protections that…

Definition

What is CWE-1038?

This vulnerability occurs when software uses automated tools to optimize code for performance or efficiency, but those optimizations accidentally weaken or bypass critical security protections that the original code relied upon.
Automated optimization tools, like aggressive compilers, minifiers, or bundlers, work by restructuring code to make it faster or smaller. However, their primary goal is efficiency, not security. In the process, they might remove security checks they deem unnecessary, inline sensitive functions, or rearrange operations in a way that breaks the logical flow designed to prevent attacks, such as timing attack mitigations or input validation sequences. Developers often trust that the original security logic will be preserved after optimization, creating a dangerous gap between code written and code executed. To prevent this, you must understand the specific behaviors of your optimization tools, test the final compiled or bundled output for security properties, and use appropriate tool configurations or code annotations to protect security-critical sections from being altered.
Real-world impact

Real-world CVEs caused by CWE-1038

  • CVE-2017-5715

    Intel, ARM, and AMD processor optimizations related to speculative execution and branch prediction cause access control checks to be bypassed when placing data into the cache. Often known as "Spectre".

  • CVE-2008-1685

    C compiler optimization, as allowed by specifications, removes code that is used to perform checks to detect integer overflows.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-1038

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Detection signals

How to detect CWE-1038

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

Plexicus auto-fix

Plexicus auto-detects CWE-1038 and opens a fix PR in under 60 seconds.

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Frequently asked questions

Frequently asked questions

What is CWE-1038?

This vulnerability occurs when software uses automated tools to optimize code for performance or efficiency, but those optimizations accidentally weaken or bypass critical security protections that the original code relied upon.

How serious is CWE-1038?

MITRE rates the likelihood of exploit as Low — exploitation is uncommon, but the weakness should still be fixed when discovered.

What languages or platforms are affected by CWE-1038?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-1038?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

How does Plexicus detect and fix CWE-1038?

Plexicus's SAST engine matches the data-flow signature for CWE-1038 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-1038?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1038.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-1038

CWE-435 Parent

Improper Interaction Between Multiple Correctly-Behaving Entities

This weakness occurs when individually secure components interact in unexpected ways within a larger system, creating new security flaws…

CWE-188 Sibling

Reliance on Data/Memory Layout

This vulnerability occurs when software incorrectly assumes how data is structured in memory or within network packets, leading to…

CWE-436 Sibling

Interpretation Conflict

An interpretation conflict occurs when two systems process the same data or sequence of events differently, leading one system to make…

CWE-439 Sibling

Behavioral Change in New Version or Environment

This vulnerability occurs when a component's behavior unexpectedly changes after an update or when deployed to a different environment,…

CWE-1037 Child

Processor Optimization Removal or Modification of Security-critical Code

This vulnerability occurs when a processor's performance optimization unintentionally strips out or alters security-critical code that a…

CWE-733 Child

Compiler Optimization Removal or Modification of Security-critical Code

This vulnerability occurs when a compiler's optimization process unintentionally strips out or alters security-critical code that a…

Resources

Further reading

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