CVE-2026-33128
7.5 · HIGHOverview
CVE-2026-33128 is a high-severity vulnerability affecting h3 h3. It was published on March 20, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
H3 is a minimal H(TTP) framework. In versions prior to 1.15.6 and between 2.0.0 through 2.0.1-rc.14, createEventStream is vulnerable to Server-Sent Events (SSE) injection due to missing newline sanitization in formatEventStreamMessage() and formatEventStreamComment(). An attacker who controls any part of an SSE message field (id, event, data, or comment) can inject arbitrary SSE events to connected clients. This issue is fixed in versions 1.15.6 and 2.0.1-rc.15.
Remediation
Check the references section for vendor advisories and patches from h3. Update h3 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| h3 | h3 | >= 0, < 1.15.6 | Affected |
Frequently Asked Questions
What is CVE-2026-33128?
CVE-2026-33128 is a high-severity vulnerability affecting h3 h3. It was published on March 20, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-33128?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-33128?
Check the references section for vendor advisories and patches from h3. Update h3 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-33128?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-33128 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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