# CVE-2024-45397: H2O alllows bypassing address-based access control with 0-RTT


- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 11 Oct 2024
- **Updated:** 11 Oct 2024
- **Also known as:** DEBIAN-CVE-2024-45397, GHSA-jf2c-xjcp-wg4c, UBUNTU-CVE-2024-45397

## What is CVE-2024-45397?

CVE-2024-45397 is a medium-severity vulnerability in h2o, published on 11 Oct 2024. 

### Official description

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When an HTTP request using TLS/1.3 early data on top of TCP Fast Open or QUIC 0-RTT packets is received and the IP-address-based access control is used, the access control does not detect and prohibit HTTP requests conveyed by packets with a spoofed source address. This behavior allows attackers on the network to execute HTTP requests from addresses that are otherwise rejected by the address-based access control. The vulnerability has been addressed in commit 15ed15a. Users may disable the use of TCP FastOpen and QUIC to mitigate the issue.

Weakness: CWE-290 (Authentication Bypass by Spoofing), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2024-45397?

It affects 1 product.


Products: Dena H2o.

## How do I fix CVE-2024-45397?

No fix has been published for CVE-2024-45397 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-45397 being exploited?

There is no known exploitation of CVE-2024-45397 in the wild and no public exploit code.

## Other vulnerabilities in h2o

- [CVE-2018-0608](https://insights.sbomify.com/CVE-2018-0608/): Memory corruption in H2O (critical 9.8)
- [CVE-2016-7835](https://insights.sbomify.com/CVE-2016-7835/): Use after free in H2O (critical 9.1)
- [CVE-2023-30847](https://insights.sbomify.com/CVE-2023-30847/): H2O vulnerable to read from uninitialized pointer in the reverse proxy handler (high 8.2)
- [CVE-2017-10868](https://insights.sbomify.com/CVE-2017-10868/): Denial of service in H2O (high 7.5)
- [CVE-2017-10869](https://insights.sbomify.com/CVE-2017-10869/): Memory corruption in H2O (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-45397 and fix it if it is affected.

What it is: CVE-2024-45397 is a medium-severity vulnerability in h2o, published on 11 Oct 2024. 
Exploitation: There is no known exploitation of CVE-2024-45397 in the wild and no public exploit code.

Affected product: h2o. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-45397/ (Markdown: https://insights.sbomify.com/CVE-2024-45397/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-45397
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-45397
- OSV: https://osv.dev/vulnerability/CVE-2024-45397

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-45397/
Summaries are generated and may contain mistakes; the official description above is the record.