# CVE-2026-34181: PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys CVE-2026-34181 is fixed in 14 products on 1 platform, first by libssl3t64 3.5.5-1ubuntu3.2, released June 8, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-34181 - Priority: High - CVSS: 9.1 (Important) - EPSS: 0.0038 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 8, 2026 - Weakness: Improper Validation of Integrity Check Value - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34181 ## Description Issue Summary: The PKCS#12 file processing fails to perform sufficient input validation for files that use Password-Based Message Authentication Code 1 (PBMAC1) integrity mechanism allowing a certificate and private key forgery. Impact Summary: An attacker impersonating a user can cause a service reading PKCS#12 files to accept forged certificates and private keys with a 1 in 256 probability. If a service accepting PKCS#12 files is using passwords for authenticating the received files, the attacker can create unencrypted PKCS#12 files that use PBMAC1 authentication that specifies an HMAC key of only one byte, allowing them to craft a file that will be accepted with a 1 in 256 probability. That would then cause the service to accept a certificate and private key controlled by the attacker. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libssl3t64 Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [libssl3t64 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libssl3t64-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 | | Linux | libssl3t64 Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [libssl3t64 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libssl3t64-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 | | Linux | openssl Debian 13.5 (trixie) | 3.5.6-1~deb13u2 | [DEBIAN-CVE-2026-34181](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34181.md) | Jun 24, 2026 | | Linux | openssl Debian 14 | 3.6.3-1 | [DEBIAN-CVE-2026-34181](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34181.md) | Jun 24, 2026 | | Linux | openssl RHEL 10 | 3.5.5-4.el10_2 | [RHSA-2026:25237](https://patchblox.com/security/data/fix/linux/rhsa-2026-25237.md) | Jun 24, 2026 | | Linux | openssl RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 | | Linux | openssl Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [openssl 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-openssl-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 | | Linux | openssl Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [openssl 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 | | Linux | openssl almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 | | Linux | openssl almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 | | Linux | openssl amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 | | Linux | openssl ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 | | Linux | openssl rocky 10 | 1:3.5.5-4.el10_2 | [RLSA-2026:25237](https://patchblox.com/security/data/fix/linux/rlsa-2026-25237.md) | Jun 13, 2026 | | Linux | openssl rocky 9 | 1:3.5.5-4.el9_8 | [RLSA-2026:25239](https://patchblox.com/security/data/fix/linux/rlsa-2026-25239.md) | Jun 13, 2026 | | Linux | openssl-3 opensuse-leap 16.0 | 3.5.0-160000.10.1 | [OPENSUSE-SU-2026:21744-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21744-1.md) | Sep 2, 2026 | | Linux | openssl-3 sles 15.7 | 3.5.0-150700.5.50.1 | [SUSE-SU-2026:4039-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4039-1.md) | Sep 7, 2026 | | Linux | openssl-3 sles 16.0 | 3.5.0-160000.10.1 | [SUSE-SU-2026:23609-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23609-1.md) | Sep 2, 2026 | | Linux | openssl-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-debugsource amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-devel RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 | | Linux | openssl-devel almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 | | Linux | openssl-devel almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 | | Linux | openssl-devel amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-devel ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 | | Linux | openssl-devel ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 | | Linux | openssl-fips-provider-latest amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-fips-provider-latest-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-libs RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 | | Linux | openssl-libs almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 | | Linux | openssl-libs almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 | | Linux | openssl-libs amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-libs ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 | | Linux | openssl-libs ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 | | Linux | openssl-libs-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-perl RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 | | Linux | openssl-perl almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 | | Linux | openssl-perl almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 | | Linux | openssl-perl amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-perl ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 | | Linux | openssl-perl ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 | | Linux | openssl-provider-legacy Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [openssl-provider-legacy 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-openssl-provider-legacy-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 | | Linux | openssl-provider-legacy Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [openssl-provider-legacy 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-provider-legacy-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 | | Linux | openssl-snapsafe-libs amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | | Linux | openssl-snapsafe-libs-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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