Bug 2564195

Summary: CVE-2026-45447 openssl3: Heap Use-After-Free in OpenSSL PKCS7_verify() [epel-all]
Product: [Fedora] Fedora EPEL Reporter: Patrick Del Bello <pdelbell>
Component: openssl3Assignee: Robert Scheck <redhat-bugzilla>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: epel10CC: dbelyavs, redhat-bugzilla
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["5c227f18-3bd4-4160-9052-6be283b47f74"]}
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Bug Blocks: 2481898    

Description Patrick Del Bello 2026-10-30 17:18:56 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Heap Use-After-Free in OpenSSL PKCS7_verify()

Heap Use-After-Free in OpenSSL PKCS7_verify() (CVE-2026-45447)
Severity: High

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.

OpenSSL 4.0, 3.6, 3.5, 3.4, 3.0, 1.1.1, and 1.0.2 are vulnerable to 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.
OpenSSL 3.4 users should upgrade to OpenSSL 3.4.6.
OpenSSL 3.0 users should upgrade to OpenSSL 3.0.21.
OpenSSL 1.1.1 users should upgrade to OpenSSL 1.1.1zh
(premium support customers only).
OpenSSL 1.0.2 users should upgrade to OpenSSL 1.0.2zq
(premium support customers only).

This issue was reported by Thai Duong (Calif.io in
collaboration with Claude and Anthropic Research).
on 27th April 2026. The fix was developed by Igor Ustinov.