# CVE-2023-46239: quic-go vulnerable to pointer dereference that can lead to panic

> A remote attacker can crash a quic-go node by triggering a nil pointer dereference during the QUIC handshake process.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Oct 2023
- **Updated:** 5 Sep 2024
- **Also known as:** GHSA-3q6m-v84f-6p9h, GO-2023-2160, UBUNTU-CVE-2023-46239

## What is CVE-2023-46239?

CVE-2023-46239 is a high-severity vulnerability in quic-go, published on 31 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

quic-go is an implementation of the QUIC protocol in Go. Starting in version 0.37.0 and prior to version 0.37.3, by serializing an ACK frame after the CRYTPO that allows a node to complete the handshake, a remote node could trigger a nil pointer dereference (leading to a panic) when the node attempted to drop the Handshake packet number space. An attacker can bring down a quic-go node with very minimal effort. Completing the QUIC handshake only requires sending and receiving a few packets. Version 0.37.3 contains a patch. Versions before 0.37.0 are not affected.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-248 (Uncaught Exception)

## Which versions are affected by CVE-2023-46239?

3 open source packages ship an affected version, including github.com/quic-go/quic-go. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/quic-go/quic-go` | Go | From 0.37.0 | 0.37.3 |
| `github.com/quic-go/quic-go` | Go | From 0.37.0 | 0.37.3 |
| `github.com/quic-go/quic-go` | Go | From 0.37.0 | 0.37.3 |

Products: Quic-Go Project Quic-Go.

## How do I fix CVE-2023-46239?

Upgrade github.com/quic-go/quic-go to 0.37.3 or later.

## Is CVE-2023-46239 being exploited?

There is no known exploitation of CVE-2023-46239 in the wild and no public exploit code.

## Other vulnerabilities in quic-go

- [CVE-2022-30591](https://insights.sbomify.com/CVE-2022-30591/): Denial of service in n/a (high 7.5)
- [CVE-2023-49295](https://insights.sbomify.com/CVE-2023-49295/): quic-go's path validation mechanism can cause denial of service (medium 6.4)
- [CVE-2026-40898](https://insights.sbomify.com/CVE-2026-40898/): quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion (medium 5.3)
- [CVE-2025-64702](https://insights.sbomify.com/CVE-2025-64702/): quic-go HTTP/3 QPACK Header Expansion DoS (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-46239 and fix it if it is affected.

What it is: CVE-2023-46239 is a high-severity vulnerability in quic-go, published on 31 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-46239 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/quic-go/quic-go (Go): affected from 0.37.0; fixed in 0.37.3
- github.com/quic-go/quic-go (Go): affected from 0.37.0; fixed in 0.37.3
- github.com/quic-go/quic-go (Go): affected from 0.37.0; fixed in 0.37.3

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-2023-46239/ (Markdown: https://insights.sbomify.com/CVE-2023-46239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-46239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-46239
- OSV: https://osv.dev/vulnerability/CVE-2023-46239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-46239/
Summaries are generated and may contain mistakes; the official description above is the record.