CVE-2021-46778
Description
A contention-based side channel vulnerability was found in hw. Some AMD CPUs using simultaneous multithreading (SMT) may allow an attacker to measure the contention level on scheduler queues, leading to potential leakage of sensitive information.
Security Bulletin
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | 5.6 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | High | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Red Hat CVSS v3 Score Explanation
The scoring is based on AMD guidance:
Also,
In a contention-based side-channel, an attacker who is able to execute code on sibling cores to leak secrets such as cryptographic keys from co-located workloads on sibling hardware threads this means (AV:L) and (AC:H)
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Acknowledgements
Red Hat would like to thank Gururaj Saileshwar of Georgia Institute of Technology, Simone Franza, Andreas Kogler and Markus Kostl of Graz University of Technology, and Stefan Gast, Daniel Gruss, Jonas Jiffinger and Martin Schwarzl of Lamarr Security Researcher/Graz University of Technology for reporting this issue.
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