What CVEs are caused by CWE-125?

4,151 recorded CVEs are attributed to CWE-125, including CVE-2026-3055, CVE-2025-5777, CVE-2026-11645. 18 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.

What are the consequences of CWE-125?

Exploiting CWE-125 can lead to: Read Memory, Bypass Protection Mechanism, DoS: Crash, Exit, or Restart, Varies by Context.

Is CWE-125 actively exploited?

Yes. 18 CWE-125 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 4,151 recorded CVEs.

Base weakness

Draft

CWE-125: Out-of-bounds Read

Also known as: OOB read

The product reads data past the end, or before the beginning, of the intended buffer.

Last updated May 1, 2026

4,151

Recorded CVEs

With this primary weakness

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Base

Abstraction

MITRE classification

Overview

CWE-125 (Out-of-bounds Read) is a base-level software weakness catalogued by MITRE in the Common Weakness Enumeration (CWE). It describes a recurring type of mistake that can lead to exploitable security vulnerabilities.

Real-world CVEs

4,151 recorded CVEs are caused by CWE-125 (Out-of-bounds Read), including 18 in CISA's KEV (Known Exploited Vulnerabilities) catalog. KEVs are shown first. 674 new CWE-125 CVEs have been recorded so far in 2026 (687 in 2025).

Showing 12 of 4,151 recorded CWE-125 CVEs. Track new ones as they are published and get AI-written analysis and fixes.

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Common consequences

What can happen when CWE-125 is exploited.

Read Memory

Affects: Confidentiality

An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.

Bypass Protection Mechanism

Affects: Confidentiality

Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.

DoS: Crash, Exit, or Restart

Affects: Availability

An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.

Varies by Context

Affects: Other

The read operation could produce other undefined or unexpected results.

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Implementation

Applies to

Languages

Memory-Unsafe

C++

Technologies

ICS/OT (Often)

How to prevent it

Practical mitigations for CWE-125, grouped by where in the lifecycle they apply.

Implementation

Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.

When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."

Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Architecture and Design

Language Selection

Use a language that provides appropriate memory abstractions.

How to detect it

Fuzzing

Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.

Effectiveness: High

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.)

Effectiveness: High

Automated Dynamic Analysis

Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518].

Effectiveness: Moderate

Code examples

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

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method

Vulnerable example

int getValueFromArray(int *array, int len, int index) {

However, this method only verifies that the given array index is less than the maximum length of the array but does not check for the minimum value (CWE-839). This will allow a negative value to be accepted as the input array index, which will result in reading data before the beginning of the buffer (CWE-127) and may allow access to sensitive memory. The input array index should be checked to verify that is within the maximum and minimum range required for the array (CWE-129). In this example the if statement should be modified to include a minimum range check, as shown below.

In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.

Vulnerable example

int processMessageFromSocket(int socket) {

However, the message length variable (msgLength) from the structure is used as the condition for ending the for loop without validating that msgLength accurately reflects the actual length of the message body (CWE-606). If msgLength indicates a length that is longer than the size of a message body (CWE-130), then this can result in a buffer over-read by reading past the end of the buffer (CWE-126).

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-2020-11899
CISA KEV
— Out-of-bounds read in IP stack used in embedded systems, as exploited in the wild per CISA KEV.
CVE-2014-0160
CISA KEV
— Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.
CVE-2023-1018 — The reference implementation code for a Trusted Platform Module does not implement length checks on data, allowing for an attacker to read 2 bytes past the end of a buffer.
CVE-2021-40985 — HTML conversion package has a buffer under-read, allowing a crash
CVE-2018-10887 — Chain: unexpected sign extension (CWE-194) leads to integer overflow (CWE-190), causing an out-of-bounds read (CWE-125)
CVE-2009-2523 — Chain: product does not handle when an input string is not NULL terminated (CWE-170), leading to buffer over-read (CWE-125) or heap-based buffer overflow (CWE-122).
CVE-2018-16069 — Chain: series of floating-point precision errors (CWE-1339) in a web browser rendering engine causes out-of-bounds read (CWE-125), giving access to cross-origin data
CVE-2004-0112 — out-of-bounds read due to improper length check
CVE-2004-0183 — packet with large number of specified elements cause out-of-bounds read.
CVE-2004-0221 — packet with large number of specified elements cause out-of-bounds read.
CVE-2004-0184 — out-of-bounds read, resultant from integer underflow
CVE-2004-1940 — large length value causes out-of-bounds read
CVE-2004-0421 — malformed image causes out-of-bounds read
CVE-2008-4113 — OS kernel trusts userland-supplied length value, allowing reading of sensitive information

Terminology & mappings

Alternate terms

OOB read: Shorthand for "Out of bounds" read

Mapped taxonomies

PLOVER: Out-of-bounds Read
CERT C Secure Coding: Do not form or use out-of-bounds pointers or array subscripts (ARR30-C) — Imprecise fit
CERT C Secure Coding: Guarantee that library functions do not form invalid pointers (ARR38-C) — Imprecise fit
CERT C Secure Coding: Do not access a variable through a pointer of an incompatible type (EXP39-C) — Imprecise fit
CERT C Secure Coding: Guarantee that storage for strings has sufficient space for character data and the null terminator (STR31-C) — Imprecise fit
CERT C Secure Coding: Do not pass a non-null-terminated character sequence to a library function that expects a string (STR32-C) — CWE More Abstract fit
Software Fault Patterns: Faulty Buffer Access (SFP8)

Attack patterns

CAPEC attack patterns that exploit this weakness.

CAPEC-540: Overread Buffers

Frequently asked questions

Common questions about CWE-125.

What is CWE-125?: The product reads data past the end, or before the beginning, of the intended buffer.
What CVEs are caused by CWE-125?: 4,151 recorded CVEs are attributed to CWE-125, including CVE-2026-3055, CVE-2025-5777, CVE-2026-11645. 18 are listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
How do you prevent CWE-125?: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
How is CWE-125 detected?: Fuzzing: Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.
What are the consequences of CWE-125?: Exploiting CWE-125 can lead to: Read Memory, Bypass Protection Mechanism, DoS: Crash, Exit, or Restart, Varies by Context.
Is CWE-125 actively exploited?: Yes. 18 CWE-125 vulnerabilities are in CISA's KEV catalog of actively exploited flaws, out of 4,151 recorded CVEs.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

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