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.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Openssl | Openssl | 1.0.2 (including) | 1.0.2zq (excluding) |
| Openssl | Openssl | 1.1.1 (including) | 1.1.1zh (excluding) |
| Openssl | Openssl | 3.0.0 (including) | 3.0.21 (excluding) |
| Openssl | Openssl | 3.4.0 (including) | 3.4.6 (excluding) |
| Openssl | Openssl | 3.5.0 (including) | 3.5.7 (excluding) |
| Openssl | Openssl | 3.6.0 (including) | 3.6.3 (excluding) |
| Openssl | Openssl | 4.0.0 (including) | 4.0.0 (including) |
| Red Hat Enterprise Linux 10 | RedHat | openssl-1:3.5.5-4.el10_2 | * |
| Red Hat Enterprise Linux 8 | RedHat | openssl-1:1.1.1k-16.el8_6 | * |
| Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | RedHat | openssl-1:1.1.1k-16.el8_6 | * |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | RedHat | openssl-1:1.1.1k-16.el8_6 | * |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | RedHat | openssl-1:1.1.1k-16.el8_6 | * |
| Red Hat Enterprise Linux 9 | RedHat | openssl-1:3.5.5-4.el9_8 | * |
| Red Hat Enterprise Linux 9 | RedHat | openssl-1:3.5.5-4.el9_8 | * |
| Red Hat Discovery 2 | RedHat | discovery/discovery-server-rhel9:1782159791 | * |
| Red Hat Discovery 2 | RedHat | discovery/discovery-ui-rhel9:1782166952 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/cds-rhel9:1781525684 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/haproxy-rhel9:1781525671 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/installer-rhel9:1781525693 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/rhua-rhel9:1781525739 | * |
| Nodejs | Ubuntu | esm-apps/jammy | * |
| Nodejs | Ubuntu | jammy | * |
| Openssl | Ubuntu | devel | * |
| Openssl | Ubuntu | esm-infra-legacy/trusty | * |
| Openssl | Ubuntu | esm-infra-legacy/xenial | * |
| Openssl | Ubuntu | esm-infra/bionic | * |
| Openssl | Ubuntu | esm-infra/focal | * |
| Openssl | Ubuntu | fips-preview/jammy | * |
| Openssl | Ubuntu | fips-updates/bionic | * |
| Openssl | Ubuntu | fips-updates/focal | * |
| Openssl | Ubuntu | fips-updates/jammy | * |
| Openssl | Ubuntu | fips/bionic | * |
| Openssl | Ubuntu | fips/focal | * |
| Openssl | Ubuntu | jammy | * |
| Openssl | Ubuntu | noble | * |
| Openssl | Ubuntu | questing | * |
| Openssl | Ubuntu | resolute | * |
| Openssl1.0 | Ubuntu | esm-infra/bionic | * |
Potential Mitigations
References
- https://github.com/openssl/openssl/commit/3aad5eb7af4de4ee0633c30a8541a54d9bbde63c
- https://github.com/openssl/openssl/commit/7d4a980c62258c5910cc883936e0c8dbab4d75a8
- https://github.com/openssl/openssl/commit/9dfd688ad2290fc5075cacbc9bf0c9a93eefed54
- https://github.com/openssl/openssl/commit/a541ae8bfe849a30cc885e8780715c0f488e496c
- https://github.com/openssl/openssl/commit/c505d7559da5d5f9f2c3913c6883a5562ce7273e
- https://openssl-library.org/news/secadv/20260609.txt
- https://access.redhat.com/errata/RHSA-2026:25237
- https://access.redhat.com/errata/RHSA-2026:25239
- https://access.redhat.com/errata/RHSA-2026:26275
- https://access.redhat.com/errata/RHSA-2026:26319
- https://access.redhat.com/errata/RHSA-2026:29197
- https://access.redhat.com/security/cve/CVE-2026-45447
- https://bugzilla.redhat.com/show_bug.cgi?id=2481898
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45447.json