An industry-wide issue was found in the way many modern microprocessor handle speculative access of system registers inaccessible to unprivileged user. It relies on the presence of a precisely-defined instruction sequence in the privileged code which allows speculative load of system registers and that such register value could be subsequently used in speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged system registers by conducting targeted cache side-channel attacks.
Find out more about CVE-2018-3640 from the MITRE CVE dictionary dictionary and NIST NVD.
This is a hardware issue and is not currently planned to be mitigated in software (in the Linux kernel). As such, we do not plan to provide mitigations for this issue in the kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7, and Red Hat Enterprise MRG 2.
Future CPU vendor microcode updates may address this issue.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 2.8 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N |
| Attack Vector | Local |
| Attack Complexity | High |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Changed |
| Confidentiality | Low |
| Integrity Impact | None |
| Availability Impact | None |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise MRG 2 | kernel-rt | Not affected |
| Red Hat Enterprise Linux 7 | kernel | Not affected |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected |
| Red Hat Enterprise Linux 7 | kernel-alt | Not affected |
| Red Hat Enterprise Linux 6 | kernel | Not affected |
| Red Hat Enterprise Linux 5 | kernel | Not affected |
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