CVE-2023-1998

Public on 2023-04-14
Modified on 2024-01-12
Description
When plain IBRS is enabled (not enhanced IBRS), the logic in spectre_v2_user_select_mitigation() determines that STIBP is not needed. The IBRS bit implicitly protects against cross-thread branch target
injection. However, with legacy IBRS, the IBRS bit is cleared on returning to userspace for performance reasons which leaves userspace threads vulnerable to cross-thread branch target injection against which STIBP protects.
Severity
Medium severity
Medium
CVSS v3 Base Score
5.6
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 1 kernel 2023-03-17 ALAS-2023-1701 Fixed
Amazon Linux 2 - Core kernel 2023-03-17 ALAS2-2023-1987 Fixed
Amazon Linux 2 - Kernel-5.10 Extra kernel 2023-03-17 ALAS2KERNEL-5.10-2023-028 Fixed
Amazon Linux 2 - Kernel-5.15 Extra kernel 2023-03-17 ALAS2KERNEL-5.15-2023-015 Fixed
Amazon Linux 2 - Kernel-5.4 Extra kernel 2023-03-17 ALAS2KERNEL-5.4-2023-043 Fixed
Amazon Linux 2023 kernel 2023-03-20 ALAS2023-2023-138 Fixed

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 5.6 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD CVSSv3 5.6 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N