CVE-2026-10740Network attack vector

Service interruption via unbounded CRYPTO frame allocation

Published Jun 10, 2026 · Updated Jun 10, 2026

Resource exhaustion in s2n-quic 1.81.0 and earlier allows remote attackers to interrupt QUIC services with crafted Initial packets. The CRYPTO frame reassembler trusts attacker-controlled frame offsets when sizing its processing buffer, so one 1,200-byte packet can trigger about 9.4 MB of allocation. No valid handshake, authentication, or user interaction is required, and repeated packets can exhaust server memory until the hosting service becomes unavailable.

CVSS severity6.9
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in s2n-quic 1.81.0 and earlier allows remote attackers to interrupt QUIC services with crafted Initial packets. The CRYPTO frame reassembler trusts attacker-controlled frame offsets when sizing its processing buffer, so one 1,200-byte packet can trigger about 9.4 MB of allocation. No valid handshake, authentication, or user interaction is required, and repeated packets can exhaust server memory until the hosting service becomes unavailable.

The record

CVE
CVE-2026-10740
Published
Jun 10, 2026
Updated
Jun 10, 2026
Vendor
Amazon Web Services
Product
s2n-quic
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Amazon Web Services · s2n-quicversion=0 <=1.8.1

Published CVSS scores

6.9Amazon Web ServicesCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
5.3Amazon Web ServicesCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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