CVE intelligence

CVE-2026-45447

Vulnerability intelligence

Published Jun 9, 2026Sources checked Nov 12, 2026

8.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-45447 and is rated High severity with a CVSS score of 8.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Citrix Security Bulletins guidance

Vendor revision: Nov 3, 2026

Vendor remediation details

We have pushed updates to both the Early Access and Normal update channels of each of XenServer 8.4 and XenServer 9. We recommend that customers update to the latest version from their chosen channel following the instructions at https://docs.xenserver.com/us/en/xenserver/8/update.html or https://docs.xenserver.com/us/en/xenserver/9/update.html We have released updated versions of Workload Balancing and Conversion Manager appliances at https://www.xenserver.com/downloads. We recommend that customers update to versions 2026.1.1 or later of Workload Balancing and 2026.2.0 of Conversion Manager.

Microsoft Security Response Center guidance

Vendor revision: Oct 16, 2026

CBL-Mariner Releases

Vendor-listed releases

3.3.7-4
20240524git3e722403cd16-18

CISA KEVNot listedBased on the latest collected catalog

EPSS4.0%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-45447?

Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.

Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution.

When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition.

In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption.

In some application contexts this may potentially be exploitable for remote code execution.

Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not affected.

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.

Source: NVD