# CVE-2026-14456: Unbounded Memory Growth in QUIC Server Incoming Channel Queue

> Remote attackers can cause denial of service in OpenSSL QUIC servers by exhausting memory through unbounded channel queue growth.

- **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:** 13 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** ALPINE-CVE-2026-14456, BELL-CVE-2026-14456, CLEANSTART-2026-IL62740, DEBIAN-CVE-2026-14456, ECHO-67da-49b3-07ec, GHSA-9x89-v382-mjh7, MINI-rm7g-mgvf-vhwq, OESA-2026-3579, ROOT-OS-DEBIAN-11-CVE-2026-14456, UBUNTU-CVE-2026-14456

## What is CVE-2026-14456?

CVE-2026-14456 is a high-severity denial of service vulnerability in OpenSSL, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: When an OpenSSL QUIC server (Listener SSL object) processes
valid QUIC Initial packets for unknown destination connection IDs, it
can allocate and queue new incoming channels without enforcing any limit.

Impact summary: A remote peer that can make many Initial packets reach the
server listener faster than the application accepts connections, can cause the
memory allocated to store the per-channel state to grow without any limits,
potentially making the QUIC listener unavailable and causing Denial of Service.

CWE: CWE-770: Allocation of Resources Without Limits or Throttling

Description: The function that handles inbound QUIC packets uses
Connection-Id from the packet header to find an existing connection
(QUIC channel). If no existing connection is found and the packet
type is INITIAL, the function treats the packet as a new connection. It
allocates a new channel object and inserts it into a queue where it
waits to be accepted by the local application with SSL_accept(3ossl).
The memory occupied by these initial channel objects may grow
without bounds if the application is not able to call SSL_accept()
frequently enough to serve these inbound connection requests.

The issue is present since OpenSSL 3.5 when the QUIC server implementation
was added.

The fix introduces a limit for pending connections. The default limit is set
to 256 pending connections (waiting to be accepted by the local application).
Applications may change the default by calling SSL_set_value_uint(3ossl).

FIPS impact: no
The FIPS module is not affected as the QUIC implementation is outside of
the OpenSSL FIPS module boundary.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-14456?


## How do I fix CVE-2026-14456?

Apply the vendor's patch.

## Is CVE-2026-14456 being exploited?

There is no known exploitation of CVE-2026-14456 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-14456 and fix it if it is affected.

What it is: CVE-2026-14456 is a high-severity denial of service vulnerability in OpenSSL, published on 13 Aug 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-2026-14456 in the wild and no public exploit code.

Affected product: 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-2026-14456/ (Markdown: https://insights.sbomify.com/CVE-2026-14456/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-14456
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14456
- OSV: https://osv.dev/vulnerability/CVE-2026-14456

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-14456/
Summaries are generated and may contain mistakes; the official description above is the record.