The flaw is an Improper Input Validation and Improper Neutralization of Special Elements in Output Used by a Downstream Component that allows a remote HTTP client to set the irc.sendTo header (and related irc.* headers). Because these header names lack the standard Camel prefix, the HttpHeaderFilterStrategy does not block them, so the incoming header values are forwarded unchanged to the IRC producer. An attacker can therefore redirect messages originally destined for a configured IRC channel or user to an arbitrary channel or nickname, potentially exfiltrating sensitive content or making the bot appear to send messages to different targets.

Affected products include Apache Camel’s IRC component. Versions from 4.0.0 up to, but not including, 4.14.8; 4.15.0 up to, but not including, 4.18.3; and 4.19.0 up to, but not including, 4.21.0 are vulnerable. The vulnerability is triggered when Camel routes bridge an HTTP consumer into an irc: producer, so any deployment that accepts HTTP requests and forwards them to IRC is at risk.

The base CVSS score of 6.5 denotes moderate severity, with potential confidentiality and integrity impact on message contents. The EPSS score of less than 1% indicates a very low likelihood of exploitation in the wild, and the issue is not listed in the CISA KEV catalog. Nevertheless, an unauthenticated HTTP client can exploit the flaw by simply including improperly prefixed irc.* headers in any request directed to the HTTP endpoint, causing the IRC producer to send messages to attacker's chosen channels or users without requiring credentials.