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Vulnerability · Published Jun 9, 2026 · Assigned by openssl

CVE-2026-45447Heap Use-After-Free in the PKCS7_verify() Function

High 8.8

In plain English

A high-severity use-after-free in OpenSSL from OpenSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 4.0% (higher than 91% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)4.0%top 9.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8compat-openssl101:1.0.2o-4.el8_10.3ALSA-2026:36215
AlmaLinux:9compat-openssl111:1.1.1k-5.el9_8.4ALSA-2026:44438
AlmaLinux:10openssl1:3.5.5-4.el10_2.alma.1ALSA-2026:25237
AlmaLinux:8openssl1:1.1.1k-16.el8_6ALSA-2026:26275
AlmaLinux:9openssl1:3.5.5-4.el9_8ALSA-2026:25239
AlmaLinux:10openssl-devel1:3.5.5-4.el10_2.alma.1ALSA-2026:25237
AlmaLinux:8openssl-devel1:1.1.1k-16.el8_6ALSA-2026:26275
AlmaLinux:9openssl-devel1:3.5.5-4.el9_8ALSA-2026:25239
AlmaLinux:10openssl-libs1:3.5.5-4.el10_2.alma.1ALSA-2026:25237
AlmaLinux:8openssl-libs1:1.1.1k-16.el8_6ALSA-2026:26275
AlmaLinux:9openssl-libs1:3.5.5-4.el9_8ALSA-2026:25239
AlmaLinux:10openssl-perl1:3.5.5-4.el10_2.alma.1ALSA-2026:25237
AlmaLinux:8openssl-perl1:1.1.1k-16.el8_6ALSA-2026:26275
AlmaLinux:9openssl-perl1:3.5.5-4.el9_8ALSA-2026:25239
Alpine:v3.21openssl3.3.7-r1ALPINE-CVE-2026-45447
Alpine:v3.22openssl3.5.7-r0ALPINE-CVE-2026-45447
Alpine:v3.23openssl3.5.7-r0ALPINE-CVE-2026-45447
Alpine:v3.24openssl3.5.7-r0ALPINE-CVE-2026-45447
Debian:12openssl3.0.20-1~deb12u2DEBIAN-CVE-2026-45447
Debian:13openssl3.5.6-1~deb13u2DEBIAN-CVE-2026-45447
Debian:14openssl3.6.3-1DEBIAN-CVE-2026-45447
Rocky Linux:8compat-openssl101:1.0.2o-4.el8_10.3RLSA-2026:36215
Rocky Linux:9compat-openssl111:1.1.1k-5.el9_8.4RLSA-2026:44438
Rocky Linux:10openssl1:3.5.5-4.el10_2RLSA-2026:25237
Rocky Linux:8openssl1:1.1.1k-16.el8_10RLSA-2026:26275
Rocky Linux:9openssl1:3.5.5-4.el9_8RLSA-2026:25239
Ubuntu:22.04:LTSedk2no fix listedUBUNTU-CVE-2026-45447
Ubuntu:24.04:LTSedk2no fix listedUBUNTU-CVE-2026-45447
Ubuntu:25.10edk2no fix listedUBUNTU-CVE-2026-45447
Ubuntu:26.04:LTSedk2no fix listedUBUNTU-CVE-2026-45447
Ubuntu:26.10edk2no fix listedUBUNTU-CVE-2026-45447
Ubuntu:26.04:LTSedk2-hweno fix listedUBUNTU-CVE-2026-45447
Ubuntu:26.10edk2-hweno fix listedUBUNTU-CVE-2026-45447
Ubuntu:22.04:LTSopenssl3.0.2-0ubuntu1.25UBUNTU-CVE-2026-45447
Ubuntu:24.04:LTSopenssl3.0.13-0ubuntu3.11UBUNTU-CVE-2026-45447
Ubuntu:25.10openssl3.5.3-1ubuntu3.4UBUNTU-CVE-2026-45447
Ubuntu:26.04:LTSopenssl3.5.5-1ubuntu3.2UBUNTU-CVE-2026-45447

Affected products (as reported)

VendorProductVersions
OpenSSL OpenSSL 4.0.0 – before 4.0.13.6.0 – before 3.6.33.5.0 – before 3.5.73.4.0 – before 3.4.63.0.0 – before 3.0.211.1.1 – before 1.1.1zh1.0.2 – before 1.0.2zq

Weakness: CWE-416, CWE-825 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References