IBM SECURITY ADVISORY First Issued: Tue Jul 21 07:48:54 CDT 2026 The most recent version of this document is available here: https://aix.software.ibm.com/aix/efixes/security/openssl_advisory48.asc Security Bulletin: Multiple vulnerabilities impact AIX due to OpenSSL =============================================================================== SUMMARY: Vulnerabilities in OpenSSL could cause denial of service (CVE-2026-9076, CVE-2026-42767, CVE-2026-42766), heap buffer overflow (CVE-2026-7383), crash and heap corruption (CVE-2026-45447), forge authentication (CVE-2026-45446), loss of confidentiality (CVE-2026-45445), credential exposure (CVE-2026-42770), bypass integrity protection (CVE-2026-34182), and heap buffer over-read (CVE-2026-34180). OpenSSL is used by AIX as part of AIX's secure network communications. =============================================================================== VULNERABILITY DETAILS: CVEID: CVE-2026-34180 https://www.cve.org/CVERecord?id=CVE-2026-34180 DESCRIPTION: Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms. CVSS Base Score: 7.5 CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2026-34182 https://www.cve.org/CVERecord?id=CVE-2026-34182 DESCRIPTION: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises. CVSS Base Score: 9.1 CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N) CVEID: CVE-2026-42766 https://www.cve.org/CVERecord?id=CVE-2026-42766 DESCRIPTION: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. CVSS Base Score: 5.9 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2026-42767 https://www.cve.org/CVERecord?id=CVE-2026-42767 DESCRIPTION: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application. CVSS Base Score: 5.9 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2026-45445 https://www.cve.org/CVERecord?id=CVE-2026-45445 DESCRIPTION: When an application drives an AES-OCB context through the public EVP_Cipher() one-shot interface, the application-supplied initialisation vector (IV) is silently discarded. CVSS Base Score: 7.5 CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N) CVEID: CVE-2026-45446 https://www.cve.org/CVERecord?id=CVE-2026-45446 DESCRIPTION: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages. CVSS Base Score: 4.8 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N) CVEID: CVE-2026-45447 https://www.cve.org/CVERecord?id=CVE-2026-45447 DESCRIPTION: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification. CVSS Base Score: 8.8 CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) CVEID: CVE-2026-7383 https://www.cve.org/CVERecord?id=CVE-2026-7383 DESCRIPTION: A signed integer overflow when sizing the destination buffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap buffer overflow. CVSS Base Score: 8.1 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) CVEID: CVE-2026-9076 https://www.cve.org/CVERecord?id=CVE-2026-9076 DESCRIPTION: When CMS password-based decryption (RFC 3211 / PWRI key unwrap) processes attacker-supplied CMS data, an attacker-chosen stream-mode KEK cipher can trigger a heap out-of-bounds read in kek_unwrap_key(). CVSS Base Score: 7.5 CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2026-42770 https://www.cve.org/CVERecord?id=CVE-2026-42770 DESCRIPTION: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer key is not properly checked for the subgroup membership. CVSS Base Score: 3.7 CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N AFFECTED PRODUCTS AND VERSIONS: AIX 7.2, 7.3 VIOS 4.1 The vulnerabilities in the following filesets are being addressed: key_fileset = osrcaix Fileset Lower Level Upper Level KEY ------------------------------------------------------ openssl.base 3.0.0.0 3.0.16.1000 key_w_fs Note: A. OpenSSL versions below 3.0 are out-of-support. Customers are advised to upgrade to OpenSSL 3.0. To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in the AIX user's guide. Example: lslpp -L | grep -i openssl.base REMEDIATION: A. FIXES IBM strongly recommends addressing the vulnerability now. A fix is available, and it can be downloaded from: https://www-01.ibm.com/marketing/iwm/iwm/web/pickUrxNew.do?source=aixbp&S_PKG=openssl To extract the fixes from the tar file: For OpenSSL 3.0: zcat openssl-3.0.21.1000.tar.Z | tar xvf - IMPORTANT: If possible, it is recommended that a mksysb backup of the system be created. Verify it is both bootable and readable before proceeding. Note that all the previously reported security vulnerability fixes are also included in above mentioned fileset level. Please refer to the readme file (provided along with the fileset) for the complete list of vulnerabilities fixed. To preview the fix installation: installp -apYd . openssl To install the fix package: installp -aXYd . openssl openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file] Published advisory OpenSSL signature file location: https://aix.software.ibm.com/aix/efixes/security/openssl_advisory48.asc.sig WORKAROUNDS AND MITIGATIONS: None. =============================================================================== CONTACT US: Note: Keywords labeled as KEY in this document are used for parsing purposes. If you would like to receive AIX Security Advisories via email, please visit "My Notifications": https://www.ibm.com/support/mynotifications Contact IBM Support for questions related to this announcement: https://ibm.com/support/ For information on how to securely verify AIX security bulletins and fixes: https://www.ibm.com/support/pages/node/6985269 To obtain the OpenSSL public key that can be used to verify the signed advisories and ifixes: Download the key from our web page: https://aix.software.ibm.com/aix/efixes/security/systems_p_os_aix_security_pubkey.txt To verify the AIX/VIOS security bulletin: Published advisory OpenSSL signature file location: https://aix.software.ibm.com/aix/efixes/security/openssl_advisory48.asc.sig openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file] Please contact your local IBM AIX support center for any assistance. REFERENCES: Review this information as needed, no action required. Complete CVSS v3 Guide: https://www.first.org/cvss/user-guide On-line Calculator v3: https://www.first.org/cvss/calculator/3.0 RELATED INFORMATION: Security Bulletin: Multiple vulnerabilities impact AIX due to OpenSSL ACKNOWLEDGEMENTS: None. CHANGE HISTORY: First Issued: Tue Jul 21 07:48:54 CDT 2026 =============================================================================== *The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin. Disclaimer According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.