BIND 9 9.16.09.16.45 cachedatabase cleanup leads to memory exhaustion
CVE-2023-6516 Published on February 13, 2024
Specific recursive query patterns may lead to an out-of-memory condition
To keep its cache database efficient, `named` running as a recursive resolver occasionally attempts to clean up the database. It uses several methods, including some that are asynchronous: a small chunk of memory pointing to the cache element that can be cleaned up is first allocated and then queued for later processing. It was discovered that if the resolver is continuously processing query patterns triggering this type of cache-database maintenance, `named` may not be able to handle the cleanup events in a timely manner. This in turn enables the list of queued cleanup events to grow infinitely large over time, allowing the configured `max-cache-size` limit to be significantly exceeded.
This issue affects BIND 9 versions 9.16.0 through 9.16.45 and 9.16.8-S1 through 9.16.45-S1.
Vulnerability Analysis
CVE-2023-6516 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2023-6516 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2023-6516
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Affected Versions
ISC BIND 9:- Version 9.16.0, <= 9.16.45 is affected.
- Version 9.16.8-S1, <= 9.16.45-S1 is affected.
- Version 9.16.0, <= 9.16.45 is affected.
- Version 9.16.8-s1, <= 9.16.45-s1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.