The speculative execution window of AMD LFENCE/JMP mitigation (MITIGATION V2-2) may be large enough to be exploited on AMD CPUs. An Intel PoC (proof of concept) demonstrates that the speculative execution window for an incorrect indirect branch prediction using an LFENCE/JMP sequence may potentially be large enough to allow exploitation using CVE-2017-5715. This was observed on AMD CPUs codenamed “Zen”, “Zen+”, “Zen 2”, and “Zen 3” using a specific workload on a Simultaneous Multi-Threading (SMT) sibling thread.
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:1975 https://access.redhat.com/errata/RHSA-2022:1975
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:1988 https://access.redhat.com/errata/RHSA-2022:1988
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2021-26401
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Extended Lifecycle Support Via RHSA-2023:0187 https://access.redhat.com/errata/RHSA-2023:0187
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2023:0399 https://access.redhat.com/errata/RHSA-2023:0399
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2023:0400 https://access.redhat.com/errata/RHSA-2023:0400