KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Configuration 1 [-]
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No data available yet.
| Source | ID | Title |
|---|---|---|
Debian DSA |
DSA-5975-1 | linux security update |
EUVD |
EUVD-2025-21959 | In the Linux kernel, the following vulnerability has been resolved: KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush In KVM guests with Hyper-V hypercalls enabled, the hypercalls HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST and HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX allow a guest to request invalidation of portions of a virtual TLB. For this, the hypercall parameter includes a list of GVAs that are supposed to be invalidated. However, when non-canonical GVAs are passed, there is currently no filtering in place and they are eventually passed to checked invocations of INVVPID on Intel / INVLPGA on AMD. While AMD's INVLPGA silently ignores non-canonical addresses (effectively a no-op), Intel's INVVPID explicitly signals VM-Fail and ultimately triggers the WARN_ONCE in invvpid_error(): invvpid failed: ext=0x0 vpid=1 gva=0xaaaaaaaaaaaaa000 WARNING: CPU: 6 PID: 326 at arch/x86/kvm/vmx/vmx.c:482 invvpid_error+0x91/0xa0 [kvm_intel] Modules linked in: kvm_intel kvm 9pnet_virtio irqbypass fuse CPU: 6 UID: 0 PID: 326 Comm: kvm-vm Not tainted 6.15.0 #14 PREEMPT(voluntary) RIP: 0010:invvpid_error+0x91/0xa0 [kvm_intel] Call Trace: vmx_flush_tlb_gva+0x320/0x490 [kvm_intel] kvm_hv_vcpu_flush_tlb+0x24f/0x4f0 [kvm] kvm_arch_vcpu_ioctl_run+0x3013/0x5810 [kvm] Hyper-V documents that invalid GVAs (those that are beyond a partition's GVA space) are to be ignored. While not completely clear whether this ruling also applies to non-canonical GVAs, it is likely fine to make that assumption, and manual testing on Azure confirms "real" Hyper-V interprets the specification in the same way. Skip non-canonical GVAs when processing the list of address to avoid tripping the INVVPID failure. Alternatively, KVM could filter out "bad" GVAs before inserting into the FIFO, but practically speaking the only downside of pushing validation to the final processing is that doing so is suboptimal for the guest, and no well-behaved guest will request TLB flushes for non-canonical addresses. |
Ubuntu USN |
USN-7879-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7880-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7879-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7934-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8028-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8028-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8031-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8028-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8028-4 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8031-2 | Linux kernel (GCP FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-6 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-8031-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8052-1 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-8028-7 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8028-8 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-8052-2 | Linux kernel (Xilinx) vulnerabilities |
Ubuntu USN |
USN-8074-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8074-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.192% probability within 30 days)
Key SSVC decision points have not yet been added.
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
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| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:* |
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| Vendors & Products |
Linux
Linux linux Kernel |
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| Metrics |
cvssV3_1
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cvssV3_1
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| Type | Values Removed | Values Added |
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| Weaknesses | CWE-754 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush In KVM guests with Hyper-V hypercalls enabled, the hypercalls HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST and HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX allow a guest to request invalidation of portions of a virtual TLB. For this, the hypercall parameter includes a list of GVAs that are supposed to be invalidated. However, when non-canonical GVAs are passed, there is currently no filtering in place and they are eventually passed to checked invocations of INVVPID on Intel / INVLPGA on AMD. While AMD's INVLPGA silently ignores non-canonical addresses (effectively a no-op), Intel's INVVPID explicitly signals VM-Fail and ultimately triggers the WARN_ONCE in invvpid_error(): invvpid failed: ext=0x0 vpid=1 gva=0xaaaaaaaaaaaaa000 WARNING: CPU: 6 PID: 326 at arch/x86/kvm/vmx/vmx.c:482 invvpid_error+0x91/0xa0 [kvm_intel] Modules linked in: kvm_intel kvm 9pnet_virtio irqbypass fuse CPU: 6 UID: 0 PID: 326 Comm: kvm-vm Not tainted 6.15.0 #14 PREEMPT(voluntary) RIP: 0010:invvpid_error+0x91/0xa0 [kvm_intel] Call Trace: vmx_flush_tlb_gva+0x320/0x490 [kvm_intel] kvm_hv_vcpu_flush_tlb+0x24f/0x4f0 [kvm] kvm_arch_vcpu_ioctl_run+0x3013/0x5810 [kvm] Hyper-V documents that invalid GVAs (those that are beyond a partition's GVA space) are to be ignored. While not completely clear whether this ruling also applies to non-canonical GVAs, it is likely fine to make that assumption, and manual testing on Azure confirms "real" Hyper-V interprets the specification in the same way. Skip non-canonical GVAs when processing the list of address to avoid tripping the INVVPID failure. Alternatively, KVM could filter out "bad" GVAs before inserting into the FIFO, but practically speaking the only downside of pushing validation to the final processing is that doing so is suboptimal for the guest, and no well-behaved guest will request TLB flushes for non-canonical addresses. | |
| Title | KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush | |
| References |
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