CVE-2025-21779

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Source
https://nvd.nist.gov/vuln/detail/CVE-2025-21779
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21779.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-21779
Downstream
Related
Published
2025-02-27T03:15:18Z
Modified
2025-07-29T11:19:07.681917Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel

Advertise support for Hyper-V's SENDIPI and SENDIPIEX hypercalls if and only if the local API is emulated/virtualized by KVM, and explicitly reject said hypercalls if the local APIC is emulated in userspace, i.e. don't rely on userspace to opt-in to KVMCAPHYPERVENFORCE_CPUID.

Rejecting SENDIPI and SENDIPI_EX fixes a NULL-pointer dereference if Hyper-V enlightenments are exposed to the guest without an in-kernel local APIC:

dumpstack+0xbe/0xfd _kasanreport.cold+0x34/0x84 kasanreport+0x3a/0x50 _apicacceptirq+0x3a/0x5c0 kvmhvsendipi.isra.0+0x34e/0x820 kvmhvhypercall+0x8d9/0x9d0 kvmemulatehypercall+0x506/0x7e0 _vmxhandleexit+0x283/0xb60 vmxhandleexit+0x1d/0xd0 vcpuenterguest+0x16b0/0x24c0 vcpurun+0xc0/0x550 kvmarchvcpuioctlrun+0x170/0x6d0 kvmvcpuioctl+0x413/0xb20 _sesysioctl+0x111/0x160 dosyscal164+0x30/0x40 entrySYSCALL64after_hwframe+0x67/0xd1

Note, checking the sending vCPU is sufficient, as the per-VM irqchip_mode can't be modified after vCPUs are created, i.e. if one vCPU has an in-kernel local APIC, then all vCPUs have an in-kernel local APIC.

References

Affected packages

Debian:11 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.237-1

Affected versions

5.*

5.10.46-4
5.10.46-5
5.10.70-1~bpo10+1
5.10.70-1
5.10.84-1
5.10.92-1~bpo10+1
5.10.92-1
5.10.92-2
5.10.103-1~bpo10+1
5.10.103-1
5.10.106-1
5.10.113-1
5.10.120-1~bpo10+1
5.10.120-1
5.10.127-1
5.10.127-2~bpo10+1
5.10.127-2
5.10.136-1
5.10.140-1
5.10.148-1
5.10.149-1
5.10.149-2
5.10.158-1
5.10.158-2
5.10.162-1
5.10.178-1
5.10.178-2
5.10.178-3
5.10.179-1
5.10.179-2
5.10.179-3
5.10.179-4
5.10.179-5
5.10.191-1
5.10.197-1
5.10.205-1
5.10.205-2
5.10.209-1
5.10.209-2
5.10.216-1
5.10.218-1
5.10.221-1
5.10.223-1
5.10.226-1
5.10.234-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:12 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.1.129-1

Affected versions

6.*

6.1.27-1
6.1.37-1
6.1.38-1
6.1.38-2~bpo11+1
6.1.38-2
6.1.38-3
6.1.38-4~bpo11+1
6.1.38-4
6.1.52-1
6.1.55-1~bpo11+1
6.1.55-1
6.1.64-1
6.1.66-1
6.1.67-1
6.1.69-1~bpo11+1
6.1.69-1
6.1.76-1~bpo11+1
6.1.76-1
6.1.82-1
6.1.85-1
6.1.90-1~bpo11+1
6.1.90-1
6.1.94-1~bpo11+1
6.1.94-1
6.1.98-1
6.1.99-1
6.1.106-1
6.1.106-2
6.1.106-3
6.1.112-1
6.1.115-1
6.1.119-1
6.1.123-1
6.1.124-1
6.1.128-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.12.16-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:11 / linux-6.1

Package

Name
linux-6.1
Purl
pkg:deb/debian/linux-6.1?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.1.129-1~deb11u1

Affected versions

6.*

6.1.106-3~deb11u1
6.1.106-3~deb11u2
6.1.106-3~deb11u3
6.1.112-1~deb11u1
6.1.119-1~deb11u1
6.1.128-1~deb11u1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}