Memory Re-orderings as a Timerless Side-channel
Summary
Researchers have provided AMD with a paper titled “MEMORY DISORDER: Memory Re-orderings as a Timerless Side-channel”
In this work, the authors introduced MEMORY DISORDER, a timerless side-channel attack that exploits memory re-orderings to infer activity on other processes. They showed that many mainstream processors were susceptible to cross-process signals and demonstrated how this vulnerability could be used to implement classic attacks, including a covert channel and application fingerprinting. The authors state these memory re-orderings can occur in CPUs and GPUs.
AMD recommends that software developers employ existing best practices, including constant-time algorithms and avoiding secret-dependent data accesses or control flows where appropriate, to help mitigate this potential vulnerability.
AMD has also created a new operating mode (AMD-SB-6010) designed to help prevent processes from running in parallel on the GPU, and to clear registers between processes on supported products. This mode is not enabled by default and needs to be set by an administrator. Instructions for enabling the new mode can be found in the relevant release notes and/or product documentation.
Acknowledgement
AMD thanks Sean Siddens, Sanya Srivastava, Reese Levine, Josiah Dykstra and Tyler Sorensen for reporting the issue and engaging in coordinated vulnerability disclosure.
Revisions
| Revision Date | Description |
| 2026-01-13 | Initial publication |
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