CVE-2024-45396Network attack vector

Process crash via inconsistent QUIC connection state

Published Oct 11, 2024 · Updated Oct 15, 2024

Reachable assertions in H2O Project quicly through d720707 allow remote attackers to crash an embedding process via crafted QUIC traffic. In lib/quicly.c, path-specific sending, connection-close retention, and receive cleanup can leave connection state inconsistent until assertions abort the process. No authentication or user interaction is required; the reported consequence is limited to availability of the embedding process.

CVSS severity7.5
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertions in H2O Project quicly through d720707 allow remote attackers to crash an embedding process via crafted QUIC traffic. In lib/quicly.c, path-specific sending, connection-close retention, and receive cleanup can leave connection state inconsistent until assertions abort the process. No authentication or user interaction is required; the reported consequence is limited to availability of the embedding process.

The record

CVE
CVE-2024-45396
Published
Oct 11, 2024
Updated
Oct 15, 2024
Vendor
H2O Project
Product
quicly
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2024Record 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 <2a95896104901589c495bc41460262e64ffcad5c
  2. Affected versionversion=< 2a95896104901589c495bc41460262e64ffcad5c

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

H2O Project · quiclyversion=0 <2a95896104901589c495bc41460262e64ffcad5c; version=< 2a95896104901589c495bc41460262e64ffcad5c

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5GitHub Security AdvisoriesCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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