# H2O Vulnerable to Denial of Service (DoS) via \`HEAD\` Request

Advisory record · `GHSA-5c8j-g96x-cj78`

- **Identifiers:** `GHSA-5c8j-g96x-cj78` · `CVE-2024-8062` · `PYSEC-2026-1438`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-1088](https://cwe.mitre.org/data/definitions/1088.html)
- **Tags:** [CWE-1088](https://agentprime.io/advisories/tag/cwe-1088.md)
- **Published:** 20 Mar 2025
- **Updated:** 7 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 20 Mar 2025, 12:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `h2o` (PyPI): affected `>=3.2.0.1, <=3.46.0`; no fixed version yet
- `ai.h2o:h2o-core` (Maven): affected `>=3.2.0.1, <=3.46.0`; no fixed version yet

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> h2o (PyPI) and ai.h2o:h2o-core (Maven), versions 3.2.0.1 through 3.46.0, are affected. The typeahead endpoint makes HEAD requests without a timeout, so an attacker who sends repeated requests that reach a server they control can make the application hang and stop serving other requests. No fixed version is listed.

Written 2 Nov 2026.

## 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 3.0: `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (@huntr_ai)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0048, the 41st percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:20 UTC: First seen by agentprime
- 31 Oct 2026, 14:20 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5c8j-g96x-cj78)

## Sources

- [GitHub Advisory Database: GHSA-5c8j-g96x-cj78](https://github.com/advisories/GHSA-5c8j-g96x-cj78)
- [OSV: GHSA-5c8j-g96x-cj78](https://osv.dev/vulnerability/GHSA-5c8j-g96x-cj78)
- <https://nvd.nist.gov/vuln/detail/CVE-2024-8062>
- <https://github.com/h2oai/h2o-3>
- <https://github.com/h2oai/h2o-3/blob/047a4d617240a56e74f834207c65973d133391cb/h2o-core/src/main/java/water/persist/PersistManager.java#L302>
- <https://huntr.com/bounties/a04190d9-4acb-449a-9a7f-f1bf6be1ed23>

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-5c8j-g96x-cj78>, 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-5c8j-g96x-cj78/>. Everything for agents: <https://agentprime.io/llms.txt>.