Google Cloud: three AMD Turin CPU flaws can leak data inside VMs
Original title: Google Cloud Warns Three AMD Turin CPU Flaws Could Leak Data Across Processes in VMs
C4D, N4D, H4D, Z4D and G4 guests need an OS fix, then a stop and start; cross-VM attacks are already mitigated.
Google Cloud said three Transient Scheduler Attacks on fifth-generation AMD EPYC Turin processors can let code on the same core infer data from other processes or the kernel inside a VM. Google rates the issue Medium and has mitigated attacks between VMs and between a VM and the host. TSA-SQ (CVE-2024-36350) and TSA-L1 (CVE-2024-36357) now affect Zen 5 differently than earlier EPYC chips; CVE-2026-0004, called TSA-Fill by Xen, can expose L1 data-cache contents. Neither Google nor AMD reports exploitation, and none is in CISA's KEV catalog.
Unconfirmed: Google does not say how customers can tell when the CPU-information update has reached a VM, and OS fixes are not yet available everywhere.
- Affected series are C4D, N4D, H4D, Z4D and G4, including C4D and Z4D bare metal.
- AMD previously said Zen 5 was not vulnerable to TSA-SQ and TSA-L1; that statement was corrected.
- Rebooting the guest is not enough after Google updates the CPU information VMs report.
- Debian has fixed CVE-2026-0004 only in unstable; bookworm, trixie and forky remain vulnerable.
- Xen says Zen 5 microcode for all TSA flaws has been in linux-firmware since September 23.
Impact: Infer process, kernel or L1 cache data on the same core
| Product | Affected |
|---|---|
| AMD EPYC Turin (Zen 5) | Zen 5 processors, including Turin |
| Google Cloud C4D, N4D, H4D, Z4D and G4 | — |
- 1.Install the OS vendor fix, then stop and start the VM after Google's CPU-information update.
- 2.On C4D or Z4D bare metal, apply the OS or hypervisor vendor fixes when available.
- 3.On customer-owned Turin hardware, apply both AMD platform firmware and OS updates.
- Organizations
- Xen Project
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2024-36350 | A transient execution vulnerability in some AMD processors may allow an attacker to infer data from previous stores, potentially resulting in the leakage of… | 5.6 | <1% | ||
| CVE-2024-36357 | A transient execution vulnerability in some AMD processors may allow an attacker to infer data in the L1D cache, potentially resulting in the leakage of… | 5.6 | <1% | ||
| CVE-2026-0004 | L1D cache leak via transient execution on some AMD CPUs | 5.7 | — |
From the original article
3 min read at thehackernews.com
Google Cloud VMs on AMD Turin chips need a guest OS patch and a stop-and-start to protect against three CPU side-channel flaws, Google said this week. The company has already applied mitigations against attacks between VMs, and between VMs and the host. Inside a VM, the flaws may let an attacker with code on the same processor core infer data from other processes or the kernel.
thehackernews.com
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