CVE-2016-0751
Description
A flaw was found in the way the Action Pack component performed MIME type lookups. Since queries were cached in a global cache of MIME types, an attacker could use this flaw to grow the cache indefinitely, potentially resulting in a denial of service.
Mitigation
Use following code to monkey-patch mime types cache and disable caching.
require 'action_dispatch/http/mime_type'
Mime.const_set :LOOKUP, Hash.new { |h,k|
Mime::Type.new(k) unless k.blank?
}
Alternatively perform filtering of mime types in the Accept header to allow only known types.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | 5 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Partial | Partial | N/A |
Vector
Red Hat: AV:N/AC:M/Au:N/C:N/I:N/A:P
NVD: AV:N/AC:L/Au:N/C:N/I:N/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Acknowledgements
Red Hat would like to thank the Ruby on Rails project for reporting this issue. Upstream acknowledges Aaron Patterson (Red Hat) as the original reporter.
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