# CVE-2026-42764: NULL Pointer Dereference in QUIC Server Initial Packet Handling

> Attackers can crash the OpenSSL QUIC server by sending invalid initial packets when address validation is disabled, causing denial of service.

- **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:** 9 Jun 2026
- **Updated:** 10 Jun 2026
- **Also known as:** ALPINE-CVE-2026-42764, BELL-CVE-2026-42764, DEBIAN-CVE-2026-42764, GHSA-5pg7-f6xv-j6m4, JLSEC-2026-1137, MINI-pp4h-f74w-w939, UBUNTU-CVE-2026-42764

## What is CVE-2026-42764?

CVE-2026-42764 is a high-severity vulnerability in Openssl Openssl, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: Receiving a QUIC initial packet with an invalid token may
trigger a NULL pointer dereference in the OpenSSL QUIC server with
address validation disabled.

Impact summary: NULL pointer dereference typically causes abnormal termination
of the affected QUIC server process and a Denial of Service.

If the address validation is disabled in the OpenSSL QUIC server
implementation, an attacker can crash the server by sending an initial
packet with an invalid or expired token.

By default, the client address validation is enabled in the OpenSSL QUIC server
implementation, which makes the default configuration not vulnerable
to this issue. However if the SSL_LISTENER_FLAG_NO_VALIDATE is used with
the SSL_new_listener() call, the address validation is disabled making the
vulnerable code reachable.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-42764?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-42764?

Apply the vendor's patch.

## Is CVE-2026-42764 being exploited?

There is no known exploitation of CVE-2026-42764 in the wild and no public exploit code.

## Other vulnerabilities in Openssl Openssl

- [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0)
- [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0)
- [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8)
- [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8)
- [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42764 and fix it if it is affected.

What it is: CVE-2026-42764 is a high-severity vulnerability in Openssl Openssl, published on 9 Jun 2026. 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-2026-42764 in the wild and no public exploit code.

Affected product: Openssl Openssl. 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-2026-42764/ (Markdown: https://insights.sbomify.com/CVE-2026-42764/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42764
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42764
- OSV: https://osv.dev/vulnerability/CVE-2026-42764

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42764/
Summaries are generated and may contain mistakes; the official description above is the record.