CVE-2026-90668
Description
A flaw was found in UnrealIRCd. The webserver component does not properly limit the number of HTTP request headers. A remote attacker can exploit this vulnerability by sending an HTTP request with an excessive number of headers, leading to memory consumption and an unresponsive server. This can result in a Denial of Service (DoS), making the server unavailable to legitimate users, particularly if a websocket or JSON-RPC listener is enabled.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
To mitigate this issue, ensure that the websocket and JSON-RPC listeners within the UnrealIRCd webserver configuration remain disabled. These listeners are not enabled by default in Red Hat's distribution of UnrealIRCd. If they have been manually enabled, disable them to prevent remote attackers from causing a denial of service through excessive HTTP request headers.
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.
Frequently Asked Questions
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