CVE-2026-42764Network attack vector

Remote server crash via NULL QUIC receiver

Published Jun 9, 2026 · Updated Jun 9, 2026

NULL pointer dereference in OpenSSL QUIC servers 3.5.0 through 3.5.6, 3.6.0 through 3.6.2, and 4.0.0 allows remote attackers to crash the process. In ssl/quic/quic_port.c, port_default_packet_handler assigns the packet receiver to qrx_src without rejecting a NULL qrx before channel binding dereferences it. The path requires SSL_new_listener() with SSL_LISTENER_FLAG_NO_VALIDATE; default address validation blocks it, and the consequence is a server-process crash.

CVSS severity7.5
High
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in OpenSSL QUIC servers 3.5.0 through 3.5.6, 3.6.0 through 3.6.2, and 4.0.0 allows remote attackers to crash the process. In ssl/quic/quic_port.c, port_default_packet_handler assigns the packet receiver to qrx_src without rejecting a NULL qrx before channel binding dereferences it. The path requires SSL_new_listener() with SSL_LISTENER_FLAG_NO_VALIDATE; default address validation blocks it, and the consequence is a server-process crash.

The record

CVE
CVE-2026-42764
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 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=3.5.0 <3.5.7
  2. Affected versionversion=3.6.0 <3.6.3
  3. Affected versionversion=4.0.0 <4.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=3.5.0 <3.5.7; version=3.6.0 <3.6.3; version=4.0.0 <4.0.1

Published CVSS scores

7.5CISA-ADPCVSS: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-476NULL Pointer Dereference
T1499.004Application 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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