CARGO · AUGUST 2026 · EARLY WARNING

s2n-quic Vulnerability: Excessive Memory Allocation Warning

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
s2n-quic (cargo)
Affected versions
< 1.31.0 or < 1.82.0 or >= 1.22.0, < 1.23.0 or >= 1.22.0, <= 1.22.0 or < 1.25.0
Patched version
v1.82.0
GHSA-9Q54-F358-3FQF

An early warning has been issued for a vulnerability in the s2n-quic Rust implementation of the QUIC protocol. Versions <= v1.81.0 are reportedly affected by excessive memory allocation, which may allow an unauthenticated user to cause a denial of service.

What happened

The s2n-quic Rust implementation of the QUIC protocol is under investigation for a vulnerability that involves excessive memory allocation. This vulnerability, if exploited, allows an unauthenticated user to send crafted CRYPTO frames that could lead to a denial of service. The versions affected are those less than or equal to v1.81.0. The vulnerability has been tracked under the ID GHSA-9Q54-F358-3FQF.

The vulnerability was first flagged on 2026-08-14T21:44:19+00:00. It is not yet confirmed to have been exploited in the wild. Software engineers using s2n-quic in their projects should assess their exposure by checking the versions in use against the affected range provided in the threat data.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If s2n-quic is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

You may be affected if your project uses s2n-quic versions < 1.31.0 or < 1.82.0 or >= 1.22.0, < 1.23.0 or >= 1.22.0, <= 1.22.0 or < 1.25.0.

What should I do right now?

Immediately upgrade to s2n-quic version v1.82.0 to mitigate the vulnerability.

Is there an official fix available?

Yes, the official fix is s2n-quic version v1.82.0.

Sources

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