# h3 has a Server-Sent Events Injection via Unsanitized Newlines in Event Stream Fields

Advisory record · `GHSA-22cc-p3c6-wpvm`

- **Identifiers:** `GHSA-22cc-p3c6-wpvm` · `CVE-2026-33128`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-93](https://cwe.mitre.org/data/definitions/93.html)
- **Tags:** [Other injection](https://agentprime.io/advisories/tag/injection.md)
- **Published:** 18 Mar 2026
- **Updated:** 20 Mar 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 18 Mar 2026, 16:17 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `h3` (npm): affected `>=2.0.0, <2.0.1-rc.15 || <1.15.6`; fixed in `2.0.1-rc.15`, `1.15.6`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0060, the 49th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 18 Mar 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-22cc-p3c6-wpvm](https://github.com/advisories/GHSA-22cc-p3c6-wpvm)
- [OSV: GHSA-22cc-p3c6-wpvm](https://osv.dev/vulnerability/GHSA-22cc-p3c6-wpvm)
- <https://github.com/h3js/h3/security/advisories/GHSA-22cc-p3c6-wpvm>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-33128>
- <https://github.com/h3js/h3/commit/7791538e15ca22437307c06b78fa155bb73632a6>
- <https://github.com/h3js/h3>
- <https://github.com/h3js/h3/blob/52c82e18bb643d124b8b9ec3b1f62b081f044611/src/utils/internal/event-stream.ts#L170-L187>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-22cc-p3c6-wpvm>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-22cc-p3c6-wpvm/>. Everything for agents: <https://agentprime.io/llms.txt>.