CVE-2026-10740: S2n quic S2n-quic Has Excessive Memory Allocation Vulnerability

MODERATE
Advisory Identifier: GHSA-9q54-f358-3fqf
Share
CVSS 5.3
CWE-770
Published
Advisory Summary

CVE-2026-10740 is a MODERATE (CVSS 5.3) s2n-quic has excessive memory allocation vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting S2n quic libraries in the crates.io ecosystem. The issue involves s2n-quic has excessive memory allocation. Remediation is available by upgrading affected packages to version 1.82.0.

CVE-2026-10740 at a Glance

CVE Identifier CVE-2026-10740
GHSA Identifier GHSA-9q54-f358-3fqf
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product S2n quic
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-10740

To remediate this vulnerability, upgrade all affected S2n quic dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

s2n-quic fixed: 1.82.0 
Upgrade s2n-quic to 1.82.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for s2n-quic

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-10740, inspect your project dependencies for S2n quic:

inspect dependencies for s2n-quic

Analyze the terminal output to locate any version of S2n quic in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.82.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In S2n quic, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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 ### Patches This issue has been addressed in s2n-quic version v1.82.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.  ### Workarounds There is no workaround that fully mitigates this issue. Upgrading to the patched version is the recommended remediation. ### References If there are any questions or comments about this advisory, contact AWS Security via the [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.

CVE-2026-10740 Affected S2n quic Versions

1 component(s)
Fixed Versions:
1.82.0
Product / Package Ecosystem Affected Versions Fixed Version
s2n-quic
 crates.io
< 1.82.0
1.82.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/aws/s2n-quic/security/advisories/GHSA-9q54-f358-3fqf
NVD — CVE-2026-10740 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-10740
S2n quic Security Information SECURITY
https://aws.amazon.com/security/security-bulletins/2026-042-aws
S2n quic Source Repository REPOSITORY
https://github.com/aws/s2n-quic
S2n quic Release RELEASE
https://github.com/aws/s2n-quic/releases/tag/v1.82.0

Frequently Asked Questions

What is CVE-2026-10740?
CVE-2026-10740 is a security vulnerability in S2n quic involving s2n-quic has excessive memory allocation under CWE-770: Allocation of Resources Without Limits or Throttling.
Which S2n quic versions are affected?
Affected versions include releases prior to 1.82.0 across affected packages: s2n-quic.
What version fixes CVE-2026-10740?
Upgrading to 1.82.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is s2n-quic affected?
Yes, s2n-quic is affected in releases prior to 1.82.0. Upgrade your dependency to 1.82.0 or later.
What is the CVSS score of CVE-2026-10740?
CVE-2026-10740 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-10740?
CVE-2026-10740 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check crates.io dependencies for CVE-2026-10740?
Run the dependency tree command: 'inspect dependencies for s2n-quic'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9q54-f358-3fqf",
  "modified" : "2026-08-14T21:44:19Z",
  "published" : "2026-08-14T21:44:19Z",
  "aliases" : [ "CVE-2026-10740" ],
  "summary" : "s2n-quic has excessive memory allocation",
  "details" : "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.\n\nImpacted versions: <= v1.81.0\n\n### Patches\nThis issue has been addressed in s2n-quic version v1.82.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. \n\n### Workarounds\nThere is no workaround that fully mitigates this issue. Upgrading to the patched version is the recommended remediation.\n\n### References\nIf there are any questions or comments about this advisory, contact AWS Security via the [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "s2n-quic"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.82.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.81.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/aws/s2n-quic/security/advisories/GHSA-9q54-f358-3fqf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-10740"
  }, {
    "type" : "WEB",
    "url" : "https://aws.amazon.com/security/security-bulletins/2026-042-aws"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aws/s2n-quic"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/aws/s2n-quic/releases/tag/v1.82.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-14T21:44:19Z",
    "nvd_published_at" : "2026-06-10T19:16:32Z"
  }
}