CVE-2026-33128
Description
A flaw was found in H3, a minimal HTTP framework. A remote attacker can exploit this flaw by injecting malicious Server-Sent Events (SSE) due to improper sanitization of newline characters in the formatEventStreamMessage() and formatEventStreamComment() functions. An attacker who controls any part of an SSE message field (id, event, data, or comment) can inject arbitrary SSE events to connected clients.
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
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Understanding the Weakness (CWE)
Integrity
Technical Impact: Unexpected State
Frequently Asked Questions
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