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CVE-2026-10740 - Excessive memory allocation in s2n-quic

0
Medium
Published: 08/20/2026 (08/20/2026, 21:35:57 UTC)
Source: AWS Security Bulletins

Description

Bulletin ID: 2026-042-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 06/10/2026 11:15 AM PDT Description: s2n-quic is a Rust implementation of the QUIC protocol. We identified CVE-2026-10740, an issue of unbounded memory allocation in the CRYPTO frame reassembler in s2n-quic before 1.82.0. 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: < v1.82.0 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.

Affected software

aws-cdk-lib
pkg:npm/aws-cdk-lib
Affected versions
<2.245.0<2.246.0

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 08/15/2026, 17:14:34 UTC

Technical Analysis

The vulnerability CVE-2026-10740 in s2n-quic involves unbounded memory allocation in the CRYPTO frame reassembler. The buffer used to process CRYPTO frames does not enforce a maximum size, allowing an unauthenticated attacker to send crafted CRYPTO frames with high offsets to exhaust server memory. This can cause denial of service without requiring a valid handshake. The issue affects all s2n-quic versions before v1.82.0. The vendor has released version v1.82.0 with a fix that addresses this excessive memory allocation. No workaround fully mitigates the issue, so upgrading is the recommended remediation.

Potential Impact

An unauthenticated attacker can cause excessive memory allocation on an s2n-quic server by sending crafted CRYPTO frames, potentially leading to denial of service due to memory exhaustion. No authentication or valid handshake is required to exploit this vulnerability.

Mitigation Recommendations

A fix is available in s2n-quic version v1.82.0. Users should upgrade to this version or later to remediate the vulnerability. There are no effective workarounds that fully mitigate this issue.

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Technical Details

Article Source
{"url":"https://aws.amazon.com/security/security-bulletins/rss/2026-041-aws/","fetched":true,"fetchedAt":"2026-06-10T18:07:49.548Z","wordCount":240}
Classification
{"confidence":0.88,"severitySource":"heuristic","classifier":"rss-v2"}

Threat ID: 6a29a7f51a07ffb497d9e114

Added to database: 06/10/2026, 18:07:49 UTC

Last enriched: 08/15/2026, 17:14:34 UTC

Last updated: 09/14/2026, 23:51:36 UTC

Views: 182

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