Bug 2481887 (CVE-2026-42764)

Summary:	CVE-2026-42764 openssl: NULL pointer dereference in QUIC server initial packet handling
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the OpenSSL QUIC (Quick UDP Internet Connections) server. A remote attacker could send a specially crafted QUIC initial packet with an invalid token. If the server's address validation is explicitly disabled, this could lead to a NULL pointer dereference, causing the server process to terminate abnormally and resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Deadline:	2026-06-09

Description OSIDB Bzimport 2026-05-27 14:09:19 UTC

NULL pointer dereference in QUIC server initial packet handling

NULL pointer dereference in QUIC server initial packet handling (CVE-2026-42764)
Severity: Moderate

Issue summary: Receiving a QUIC initial packet with an invalid token may
trigger a NULL pointer dereference in the OpenSSL QUIC server with
address validation disabled.

Impact summary: NULL pointer dereference typically causes abnormal termination
of the affected QUIC server process and a Denial of Service.

If the address validation is disabled in the OpenSSL QUIC server
implementation, an attacker can crash the server by sending an initial
packet with an invalid or expired token.

By default, the client address validation is enabled in the OpenSSL QUIC server
implementation, which makes the default configuration not vulnerable
to this issue. However if the SSL_LISTENER_FLAG_NO_VALIDATE is used with
the SSL_new_listener() call, the address validation is disabled making the
vulnerable code reachable.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary.

OpenSSL 4.0, 3.6, and 3.5 are vulnerable to this issue.

OpenSSL 3.4, 3.0, 1.1.1, and 1.0.2 are not affected by this issue.

OpenSSL 4.0 users should upgrade to OpenSSL 4.0.1
OpenSSL 3.6 users should upgrade to OpenSSL 3.6.3
OpenSSL 3.5 users should upgrade to OpenSSL 3.5.7

This issue was reported and the fix submitted on 27th March 2026
by Sunwoo Lee (KENTECH), Hyuk Lim (KENTECH) and Seunghyun Yoon (KENTECH).

Comment 2 errata-xmlrpc 2026-06-11 12:31:59 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:25237 https://access.redhat.com/errata/RHSA-2026:25237

Comment 3 errata-xmlrpc 2026-06-11 12:34:31 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:25239 https://access.redhat.com/errata/RHSA-2026:25239