Description
The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count.
Reference counts can be used when tracking how many objects contain a reference to a particular resource, such as in memory management or garbage collection. When the reference count reaches zero, the resource can be de-allocated or reused because there are no more objects that use it. If the reference count accidentally reaches zero, then the resource might be released too soon, even though it is still in use. If all objects no longer use the resource, but the reference count is not zero, then the resource might not ever be released.
Potential Impact
Availability
DoS: Resource Consumption (Memory), DoS: Resource Consumption (Other)
Availability
DoS: Crash, Exit, or Restart
Real-World CVE Examples
| CVE ID | Description |
|---|---|
| CVE-2002-0574 | chain: reference count is not decremented, leading to memory leak in OS by sending ICMP packets. |
| CVE-2004-0114 | Reference count for shared memory not decremented when a function fails, potentially allowing unprivileged users to read kernel memory. |
| CVE-2006-3741 | chain: improper reference count tracking leads to file descriptor consumption |
| CVE-2007-1383 | chain: integer overflow in reference counter causes the same variable to be destroyed twice. |
| CVE-2007-1700 | Incorrect reference count calculation leads to improper object destruction and code execution. |
| CVE-2008-2136 | chain: incorrect update of reference count leads to memory leak. |
| CVE-2008-2785 | chain/composite: use of incorrect data type for a reference counter allows an overflow of the counter, leading to a free of memory that is still in use. |
| CVE-2008-5410 | Improper reference counting leads to failure of cryptographic operations. |
| CVE-2009-1709 | chain: improper reference counting in a garbage collection routine leads to use-after-free |
| CVE-2009-3553 | chain: reference count not correctly maintained when client disconnects during a large operation, leading to a use-after-free. |
| CVE-2009-3624 | Reference count not always incremented, leading to crash or code execution. |
| CVE-2010-0176 | improper reference counting leads to expired pointer dereference. |
| CVE-2010-0623 | OS kernel increments reference count twice but only decrements once, leading to resource consumption and crash. |
| CVE-2010-2549 | OS kernel driver allows code execution |
| CVE-2010-4593 | improper reference counting leads to exhaustion of IP addresses |
Showing 15 of 17 observed examples.
Related Weaknesses
Frequently Asked Questions
What is CWE-911?
CWE-911 (Improper Update of Reference Count) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Base-level weakness. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count.
How can CWE-911 be exploited?
Attackers can exploit CWE-911 (Improper Update of Reference Count) to dos: resource consumption (memory), dos: resource consumption (other). This weakness is typically introduced during the Implementation phase of software development.
How do I prevent CWE-911?
Follow secure coding practices, conduct code reviews, and use automated security testing tools (SAST/DAST) to detect this weakness early in the development lifecycle.
What is the severity of CWE-911?
CWE-911 is classified as a Base-level weakness (Medium abstraction). It has been observed in 17 real-world CVEs.