The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

Primary

Implementation

Availability
DoS: Resource Consumption (CPU)
DoS: Resource Consumption (Memory)
DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.

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.)
High

In the following code the method processMessagesFromServer attempts to establish a connection to a server and read and process messages from the server. The method uses a do/while loop to continue trying to establish the connection to the server when an attempt fails.

int processMessagesFromServer(char *hostaddr, int port) {
...int servsock;int connected;struct sockaddr_in servaddr;

// create socket to connect to server
servsock = socket( AF_INET, SOCK_STREAM, 0);memset( &servaddr, 0, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(port);servaddr.sin_addr.s_addr = inet_addr(hostaddr);
do {

// establish connection to server
connected = connect(servsock, (struct sockaddr *)&servaddr, sizeof(servaddr));

// if connected then read and process messages from server
if (connected > -1) {

// read and process messages
...
}

// keep trying to establish connection to the server
} while (connected < 0);

// close socket and return success or failure
...
}

However, this will create an infinite loop if the server does not respond. This infinite loop will consume system resources and can be used to create a denial of service attack. To resolve this a counter should be used to limit the number of attempts to establish a connection to the server, as in the following code.

int processMessagesFromServer(char *hostaddr, int port) {
...
// initialize number of attempts counter
int count = 0;do {

// establish connection to server
connected = connect(servsock, (struct sockaddr *)&servaddr, sizeof(servaddr));

// increment counter
count++;

// if connected then read and process messages from server
if (connected > -1) {

// read and process messages
...
}

// keep trying to establish connection to the server

// up to a maximum number of attempts
} while (connected < 0 && count < MAX_ATTEMPTS);

// close socket and return success or failure
...
}

For this example, the method isReorderNeeded is part of a bookstore application that determines if a particular book needs to be reordered based on the current inventory count and the rate at which the book is being sold.

public boolean isReorderNeeded(String bookISBN, int rateSold) {

boolean isReorder = false;
int minimumCount = 10;int days = 0;

// get inventory count for book
int inventoryCount = inventory.getIventoryCount(bookISBN);

// find number of days until inventory count reaches minimum
while (inventoryCount > minimumCount) {

inventoryCount = inventoryCount - rateSold;days++;

}

// if number of days within reorder timeframe

// set reorder return boolean to true
if (days > 0 && days < 5) {isReorder = true;}
return isReorder;
}

However, the while loop will become an infinite loop if the rateSold input parameter has a value of zero since the inventoryCount will never fall below the minimumCount. In this case the input parameter should be validated to ensure that a value of zero does not cause an infinite loop, as in the following code.

public boolean isReorderNeeded(String bookISBN, int rateSold) {
...

// validate rateSold variable
if (rateSold < 1) {return isReorder;}
...
}

CVE-2022-22224
Chain: an operating system does not properly process malformed Open Shortest Path First (OSPF) Type/Length/Value Identifiers (TLV) (CWE-703), which can cause the process to enter an infinite loop (CWE-835)
https://www.cve.org/CVERecord?id=CVE-2022-22224

CVE-2022-25304
A Python machine communication platform did not account for receiving a malformed packet with a null size, causing the receiving function to never update the message buffer and be caught in an infinite loop.
https://www.cve.org/CVERecord?id=CVE-2022-25304

CVE-2011-1027
Chain: off-by-one error (CWE-193) leads to infinite loop (CWE-835) using invalid hex-encoded characters.
https://www.cve.org/CVERecord?id=CVE-2011-1027

CVE-2011-1142
Chain: self-referential values in recursive definitions lead to infinite loop.
https://www.cve.org/CVERecord?id=CVE-2011-1142

CVE-2011-1002
NULL UDP packet is never cleared from a queue, leading to infinite loop.
https://www.cve.org/CVERecord?id=CVE-2011-1002

CVE-2006-6499
Chain: web browser crashes due to infinite loop - "bad
looping logic [that relies on] floating point math [CWE-1339] to exit
the loop [CWE-835]"
https://www.cve.org/CVERecord?id=CVE-2006-6499

CVE-2010-4476
Floating point conversion routine cycles back and forth between two different values.
https://www.cve.org/CVERecord?id=CVE-2010-4476

CVE-2010-4645
Floating point conversion routine cycles back and forth between two different values.
https://www.cve.org/CVERecord?id=CVE-2010-4645

CVE-2010-2534
Chain: improperly clearing a pointer in a linked list leads to infinite loop.
https://www.cve.org/CVERecord?id=CVE-2010-2534

CVE-2013-1591
Chain: an integer overflow (CWE-190) in the image size calculation causes an infinite loop (CWE-835) which sequentially allocates buffers without limits (CWE-1325) until the stack is full.
https://www.cve.org/CVERecord?id=CVE-2013-1591

CVE-2008-3688
Chain: A denial of service may be caused by an uninitialized variable (CWE-457) allowing an infinite loop (CWE-835) resulting from a connection to an unresponsive server.
https://www.cve.org/CVERecord?id=CVE-2008-3688

ASCSM-CWE-835

Allowed
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

CWE Content Team
MITRE
2011-03-22
1.12
2011-03-30

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2012-05-11
updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2017-11-08
updated Demonstrative_Examples

CWE Content Team
MITRE
2019-01-03
updated References, Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2019-06-20
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated Relationships

CWE Content Team
MITRE
2020-08-20
updated Relationships

CWE Content Team
MITRE
2020-12-10
updated Observed_Examples, Relationships

CWE Content Team
MITRE
2021-03-15
updated Observed_Examples

CWE Content Team
MITRE
2021-07-20
updated Observed_Examples

CWE Content Team
MITRE
2023-01-31
updated Description, Observed_Examples

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes

CWE Content Team
MITRE
2023-10-26
updated Observed_Examples

CWE Content Team
MITRE
2024-02-29
4.14
2024-02-29
updated Demonstrative_Examples

CWE Content Team
MITRE
2024-11-19
4.16
2024-11-19
updated Description, Diagram

CWE Content Team
MITRE
2025-12-11
4.19
2025-12-11
updated Applicable_Platforms, Detection_Factors, Time_of_Introduction, Weakness_Ordinalities

Abhi Balakrishnan
2024-09-29
4.16
2024-11-19
Contributed usability diagram concepts used by the CWE team