CAPEC-10

Although the focus of this attack is putting excessive content into an environment variable that is loaded into a buffer, environment variables can be used to assist a classic buffer overflow attack as well. In the case where the buffer used in a traditional buffer overflow attack is not large enough to store the adversary's shell code, they will store the shell code in an environment variable and attempt to return to its address, rather than back into the data they wrote to the buffer.

How the attack unfolds

1. Explore

   The attacker looks for a way in.

   1. [Identify target application] The adversary identifies a target application or program to perform the buffer overflow on. In this attack the adversary looks for an application that loads the content of an environment variable into a buffer.

2. Experiment

   They probe what they found.

   2. [Find injection vector] The adversary identifies an injection vector to deliver the excessive content to the targeted application's buffer.

      1 technique

      • Change the values of environment variables thought to be used by the application to contain excessive data. If the program is loading the value of the environment variable into a buffer, this could cause a crash and an attack vector will be found.

   3. [Craft overflow content] The adversary crafts the content to be injected. If the intent is to simply cause the software to crash, the content need only consist of an excessive quantity of random data. If the intent is to leverage the overflow for execution of arbitrary code, the adversary crafts the payload in such a way that the overwritten return address is replaced with one of the adversary's choosing.

      2 techniques

      • Create malicious shellcode that will execute when the program execution is returned to it.
      • Use a NOP-sled in the overflow content to more easily "slide" into the malicious code. This is done so that the exact return address need not be correct, only in the range of all of the NOPs

3. Exploit

   They carry out the attack.

   4. [Overflow the buffer] Using the injection vector, the adversary injects the crafted overflow content into the buffer.

Prerequisites

• The application uses environment variables.

• An environment variable exposed to the user is vulnerable to a buffer overflow.

• The vulnerable environment variable uses untrusted data.

• Tainted data used in the environment variables is not properly validated. For instance boundary checking is not done before copying the input data to a buffer.

Skills required

• Low skill

  An attacker can simply overflow a buffer by inserting a long string into an attacker-modifiable injection vector. The result can be a DoS.

• High skill

  Exploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level.

Signs of an attack

• If the application does bound checking, it should fail when the data source is larger than the size of the destination buffer. If the application's code is well written, that failure should trigger an alert.

Consequences

Mitigations

• Do not expose environment variable to the user.

• Do not use untrusted data in your environment variables.

• Use a language or compiler that performs automatic bounds checking

• There are tools such as Sharefuzz [REF-2] which is an environment variable fuzzer for Unix that support loading a shared library. You can use Sharefuzz to determine if you are exposing an environment variable vulnerable to buffer overflow.

Weaknesses it exploits

• CWE-20 Improper Input Validation
• CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
• CWE-99 Improper Control of Resource Identifiers
• CWE-118 Incorrect Access of Indexable Resource
• CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
• CWE-120 Buffer Copy without Checking Size of Input
• CWE-302 Authentication Bypass by Assumed-Immutable Data
• CWE-680 Integer Overflow to Buffer Overflow
• CWE-697 Incorrect Comparison
• CWE-733 Compiler Optimization Removal or Modification of Security-critical Code

Recent CVEs with these weaknesses

1. 9.6CVE-2026-1081862026-11-10

   Improper Input Validation in Zoom Workplace for Windows may allow an unauthenticated user to conduct an escalation of privilege via network access.

2. 4.9CVE-2026-1054272026-11-10

   Improper input validation in Ivanti EPMM before version 12.10.0.1, 12.9.0.3, and 12.8.0.5 allows a remote authenticated attacker with admin privileges to permanently disable all Apache HTTPS services resulting in denial of service.

3. 6.7CVE-2026-1054262026-11-10

   Improper input validation in Ivanti EPMM before version 12.10.0.1, 12.9.0.3, and 12.8.0.5 allows a remote authenticated attacker with admin privileges to set arbitrary Linux kernel parameters as root.

4. 4.3CVE-2026-1231782026-11-10

   An insufficient input validation vulnerability in the listed NETGEAR Orbi Models router allows an authenticated administrator connected to the local network to execute unauthorized commands and modify the router’s software and functionalit…

5. 8.8CVE-2026-1249482026-11-10

   Incorrect boundary conditions, use-after-free in the Graphics component. This vulnerability was fixed in Firefox 160 and Firefox ESR 153.7.

6. 8.8CVE-2026-1249472026-11-10

   Incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 160.

7. 8.8CVE-2026-1249262026-11-10

   Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 160 and Firefox ESR 153.7.

8. 8.8CVE-2026-1249242026-11-10

   Incorrect boundary conditions in the Graphics: WebRender component. This vulnerability was fixed in Firefox 160 and Firefox ESR 153.7.

The newest records naming one of them. Each weakness's page lists them all.

Related attack patterns

Part of

• CAPEC-100 Overflow Buffers

Examples

MITRE's words, unchanged: CAPEC-10 at MITRE. CAPEC is Copyright © 2007–2026, The MITRE Corporation, used under the CAPEC terms of use: “The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use Common Attack Pattern Enumeration and Classification (CAPEC™) for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE’s copyright designation and this license in any such copy.” CAPEC and the CAPEC logo are trademarks of The MITRE Corporation. Credits. All attack patterns.