In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated Explicitly set/clear CR8 write interception when AVIC is (de)activated to fix a bug where KVM leaves the interception enabled after AVIC is activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8 will remain intercepted in perpetuity. On its own, the dangling CR8 intercept is "just" a performance issue, but combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM: Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging intercept is fatal to Windows guests as the TPR seen by hardware gets wildly out of sync with reality. Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this is firmly an SVM implementation flaw/detail. WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should never enter the guest with AVIC enabled and CR8 writes intercepted. [Squash fix to avic_deactivate_vmcb. - Paolo]
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated Explicitly set/clear CR8 write interception when AVIC is (de)activated to fix a bug where KVM leaves the interception enabled after AVIC is activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8 will remain intercepted in perpetuity. On its own, the dangling CR8 intercept is "just" a performance issue, but combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM: Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging intercept is fatal to Windows guests as the TPR seen by hardware gets wildly out of sync with reality. Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this is firmly an SVM implementation flaw/detail. WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should never enter the guest with AVIC enabled and CR8 writes intercepted. [Squash fix to avic_deactivate_vmcb. - Paolo]
Update Linux/Linux to a4123fe5d9122eef9852e4921f7cc463420f30d4 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanKVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated affects Linux/Linux (generic), Linux/Linux (generic). Severity is medium. In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated Explicitly set/clear CR8 write interception when AVIC is (de)activated to fix a bug where KVM leaves the interception enabled after AVIC is activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8 will remain intercepted in perpetuity. On its own, the dangling CR8 intercept is "just" a performance issue, but combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM: Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging intercept is fatal to Windows guests as the TPR seen by hardware gets wildly out of sync with reality. Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this is firmly an SVM implementation flaw/detail. WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should never enter the guest with AVIC enabled and CR8 writes intercepted. [Squash fix to avic_deactivate_vmcb. - Paolo]
AI coding agents often install or upgrade packages automatically in generic. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <a4123fe5d9122eef9852e4921f7cc463420f30d4 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <816fa1dfae4532e851b1fe6b2434c753ecbd86c7 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <01651e7751edbbc0fb4598f8367a3dabcfc8c182 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <ba3bca40f9f25c053f69413e5f4a41dd0fd762bf || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <737410b32bd615b321da4fbeda490351b9af5e8b || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <87d0f901a9bd8ae6be57249c737f20ac0cace93d | a4123fe5d9122eef9852e4921f7cc463420f30d4, 816fa1dfae4532e851b1fe6b2434c753ecbd86c7, 01651e7751edbbc0fb4598f8367a3dabcfc8c182, ba3bca40f9f25c053f69413e5f4a41dd0fd762bf, 737410b32bd615b321da4fbeda490351b9af5e8b, 87d0f901a9bd8ae6be57249c737f20ac0cace93d |
| Linux/Linuxgeneric | 4.7 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate Linux/Linux to a4123fe5d9122eef9852e4921f7cc463420f30d4 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanKVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated affects Linux/Linux (generic), Linux/Linux (generic). Severity is medium. In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated Explicitly set/clear CR8 write interception when AVIC is (de)activated to fix a bug where KVM leaves the interception enabled after AVIC is activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8 will remain intercepted in perpetuity. On its own, the dangling CR8 intercept is "just" a performance issue, but combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM: Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging intercept is fatal to Windows guests as the TPR seen by hardware gets wildly out of sync with reality. Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this is firmly an SVM implementation flaw/detail. WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should never enter the guest with AVIC enabled and CR8 writes intercepted. [Squash fix to avic_deactivate_vmcb. - Paolo]
AI coding agents often install or upgrade packages automatically in generic. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <a4123fe5d9122eef9852e4921f7cc463420f30d4 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <816fa1dfae4532e851b1fe6b2434c753ecbd86c7 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <01651e7751edbbc0fb4598f8367a3dabcfc8c182 || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <ba3bca40f9f25c053f69413e5f4a41dd0fd762bf || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <737410b32bd615b321da4fbeda490351b9af5e8b || >=3bbf3565f48ce3999b5a12cde946f81bd4475312 <87d0f901a9bd8ae6be57249c737f20ac0cace93d | a4123fe5d9122eef9852e4921f7cc463420f30d4, 816fa1dfae4532e851b1fe6b2434c753ecbd86c7, 01651e7751edbbc0fb4598f8367a3dabcfc8c182, ba3bca40f9f25c053f69413e5f4a41dd0fd762bf, 737410b32bd615b321da4fbeda490351b9af5e8b, 87d0f901a9bd8ae6be57249c737f20ac0cace93d |
| Linux/Linuxgeneric | 4.7 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard