CVE-2026-3104
Memory Leak in BIND 9 Resolver via Crafted Domain Query
Publication date: 2026-03-25
Last updated on: 2026-03-25
Assigner: Internet Systems Consortium (ISC)
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| isc | bind | From 9.20.0 (inc) to 9.20.20 (inc) |
| isc | bind | From 9.21.0 (inc) to 9.21.19 (inc) |
| isc | bind | From 9.20.9-s1 (inc) to 9.20.20-s1 (inc) |
| isc | bind | From 9.18.0 (inc) to 9.18.46 (inc) |
| isc | bind | From 9.18.11-s1 (inc) to 9.18.46-s1 (inc) |
| isc | bind | From 9.20.9-S1 (inc) to 9.20.20-S1 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-772 | The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability causes a memory leak in the BIND resolver process named, leading to unbounded growth in Resident Set Size (RSS) memory usage.
To detect this vulnerability on your system, monitor the memory usage of the named process for unusual or continuous growth, which may indicate the memory leak is active.
You can use commands such as:
- Linux: `ps aux | grep named` to check memory usage of the named process.
- Linux: `top` or `htop` to observe real-time memory consumption of named.
- Linux: `pmap <pid_of_named>` to get detailed memory map of the named process.
- Linux: `cat /proc/<pid_of_named>/status | grep VmRSS` to check Resident Set Size memory.
Additionally, if the named process crashes with an assertion failure during shutdown or reload, this may also indicate the presence of the vulnerability.
What immediate steps should I take to mitigate this vulnerability?
The recommended immediate mitigation step is to upgrade your BIND resolver software to a patched version.
- Upgrade to BIND versions 9.20.21, 9.21.20, or 9.20.21-S1 (Supported Preview Edition) as these versions contain the fix for the memory leak.
No workarounds are known for this vulnerability, so upgrading is the only effective mitigation.
Monitor the named process for abnormal memory usage and avoid restarting or reloading the service while the leak is active to prevent assertion failures.
Can you explain this vulnerability to me?
This vulnerability involves a specially crafted domain name that can cause a memory leak in the BIND DNS resolver when queried.
It affects specific versions of BIND 9, namely versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.
Other versions such as 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are not affected.
How can this vulnerability impact me? :
The vulnerability can lead to a memory leak in the BIND resolver, which may cause the affected system to consume increasing amounts of memory over time.
This can degrade system performance or potentially cause a denial of service if the memory exhaustion becomes severe.