CVE-2026-10740: s2n-quic has excessive memory allocation

August 14, 2026

s2n-quic is a Rust implementation of the QUIC protocol. An unauthenticated user can attempt to exhaust server memory on an s2n-quic endpoint by sending crafted CRYPTO frames with high offsets. The buffer used for processing CRYPTO frames does not enforce a maximum size. In the worst case, a single 1200-byte packet can cause approximately 9.4 MB of allocation. By repeatedly sending such packets, the resulting memory pressure could cause denial of service. No valid handshake is required.

Impacted versions: <= v1.81.0

References

aws.amazon.com/security/security-bulletins/2026-042-aws
github.com/advisories/GHSA-9q54-f358-3fqf
github.com/aws/s2n-quic/releases/tag/v1.82.0
github.com/aws/s2n-quic/security/advisories/GHSA-9q54-f358-3fqf
nvd.nist.gov/vuln/detail/CVE-2026-10740

Code Behaviors & Features

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