Bug 2430390 (CVE-2026-22796)

Summary:	CVE-2026-22796 openssl: OpenSSL: Denial of Service via type confusion in PKCS#7 signature verification
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	csutherl, jclere, pjindal, plodge, security-response-team, szappis, vchlup
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in OpenSSL. This type confusion vulnerability allows a remote attacker to cause a denial of service (DoS) by providing specially crafted PKCS#7 data to an application that performs signature verification. The vulnerability occurs because the application accesses an ASN1_TYPE union member without proper type validation, leading to an invalid or NULL pointer dereference and a crash.	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:	2026-01-27

Description OSIDB Bzimport 2026-01-16 14:45:00 UTC

Severity: Low

Issue summary: A type confusion vulnerability exists in the signature
verification of signed PKCS#7 data where an ASN1_TYPE union member is
accessed without first validating the type, causing an invalid or NULL
pointer dereference when processing malformed PKCS#7 data.

Impact summary: An application performing signature verification of PKCS#7
data or calling directly the PKCS7_digest_from_attributes() function can be
caused to dereference an invalid or NULL pointer when reading, resulting in
a Denial of Service.

The function PKCS7_digest_from_attributes() accesses the message digest attribute
value without validating its type. When the type is not V_ASN1_OCTET_STRING,
this results in accessing invalid memory through the ASN1_TYPE union, causing
a crash.

Exploiting this vulnerability requires an attacker to provide a malformed
signed PKCS#7 to an application that verifies it. The impact of the
exploit is just a Denial of Service, the PKCS7 API is legacy and applications
should be using the CMS API instead. For these reasons the issue was
assessed as Low severity.

The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the PKCS#7 parsing implementation is outside the OpenSSL FIPS module
boundary.

OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.

OpenSSL 3.6 users should upgrade to OpenSSL 3.6.1.

OpenSSL 3.5 users should upgrade to OpenSSL 3.5.5.

OpenSSL 3.4 users should upgrade to OpenSSL 3.4.4.

OpenSSL 3.3 users should upgrade to OpenSSL 3.3.6.

OpenSSL 3.0 users should upgrade to OpenSSL 3.0.19.

OpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1ze.
(premium support customers only).

OpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zn.
(premium support customers only).

Comment 2 errata-xmlrpc 2026-01-28 08:56:46 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:1472 https://access.redhat.com/errata/RHSA-2026:1472

Comment 3 errata-xmlrpc 2026-01-28 09:54:16 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:1473 https://access.redhat.com/errata/RHSA-2026:1473