CVE-2020-37127
Buffer Overflow in Dnsmasq-utils dhcp_release Causes DoS
Publication date: 2026-02-05
Last updated on: 2026-02-05
Assigner: VulnCheck
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| the_dnsmasq_project | dnsmasq | 2.79-1 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-121 | A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
Dnsmasq-utils version 2.79-1 contains a buffer overflow vulnerability in the dhcp_release utility. This vulnerability occurs because the program copies input into a fixed-size buffer without proper bounds checking. Specifically, if an attacker supplies an input string longer than 16 characters, it causes a buffer overflow.
This overflow can cause the dhcp_release process to crash and produce a core dump, effectively causing a denial of service.
How can this vulnerability impact me? :
This vulnerability can be exploited by an attacker to cause a denial of service (DoS) on systems running the vulnerable dhcp_release utility. By sending a specially crafted input longer than 16 characters, the attacker can crash the dhcp_release process, potentially disrupting DHCP lease management.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
[{'type': 'paragraph', 'content': 'This vulnerability can be detected by testing the dhcp_release utility with input strings longer than 16 characters to see if it crashes or produces a core dump.'}, {'type': 'paragraph', 'content': "A practical detection method is to run the dhcp_release command with an argument consisting of a long string, such as a sequence of 'A' characters exceeding 16 in length."}, {'type': 'paragraph', 'content': 'For example, you can use the following command in a Linux shell to test the vulnerability:'}, {'type': 'list_item', 'content': 'python3 -c "import os; os.system(\'dhcp_release \' + \'A\'*20)"'}, {'type': 'paragraph', 'content': 'If the dhcp_release process aborts and generates a core dump, it indicates the presence of the buffer overflow vulnerability.'}] [2]
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, avoid using the vulnerable dhcp_release utility with untrusted or excessively long input strings.
Immediate steps include:
- Restrict access to the dhcp_release utility to trusted users only.
- Monitor and filter inputs to dhcp_release to ensure they do not exceed 16 characters.
- Apply any available patches or updates from your distribution or the dnsmasq project that address this buffer overflow.
If no patch is available, consider disabling or replacing the dhcp_release utility until a fix is applied.