Three essential vulnerabilities in XenServer VM Instruments for Home windows permit attackers to execute arbitrary code and escalate privileges inside visitor working programs.
The issues, recognized as CVE-2025-27462, CVE-2025-27463, and CVE-2025-27464, have an effect on all variations of XenServer VM Instruments for Home windows earlier than 9.4.1.
The vulnerabilities had been publicly disclosed as a part of Xen Safety Advisory, prompting quick motion from virtualization platform directors worldwide.
These safety flaws pose a big danger to enterprise environments that run Home windows digital machines on XenServer and Citrix Hypervisor platforms.
Xen Home windows PV Driver Flaws
The vulnerabilities stem from extreme permissions on user-exposed gadgets inside the Home windows PV drivers, particularly affecting three core elements: XenCons, XenIface, and XenBus.
In response to the safety advisory, these elements “haven’t any safety descriptor, and are due to this fact absolutely accessible to unprivileged customers”.
XenCons driver vulnerability (CVE-2025-27462) was first launched in model 9.0.0 and has been susceptible since its preliminary launch.
The XenIface (CVE-2025-27463) and XenBus (CVE-2025-27464) drivers are susceptible throughout all releases, making this a widespread subject affecting quite a few enterprise deployments.
Affected programs embody Home windows digital machines working on XenServer 8.4 and Citrix Hypervisor 8.2 CU1 LTSR.
Particularly, XCP-ng PV Bus, XCP-ng Interface, and XCP-ng PV Console variations older than 9.0.9065 are susceptible, whereas XenServer/Citrix PV Bus variations older than 9.1.11.115 and PV Interface variations older than 9.1.12.94 are additionally in danger.
The vulnerabilities allow unprivileged customers inside Home windows visitor working programs to escalate privileges to that of the visitor kernel. This represents a essential safety breach as attackers with restricted entry can acquire full management over the affected digital machine.
The CVSSv4.0 rating for these vulnerabilities is 5.9, labeled as “Low” danger based on some assessments, however the sensible affect is extreme.
An attacker exploiting these flaws can execute arbitrary code with system-level privileges, doubtlessly compromising delicate knowledge, putting in malware, or utilizing the compromised VM as a pivot level for lateral motion inside the community.
The exploitation vector is native, which means attackers should have already got some degree of entry to the Home windows visitor system.
Nevertheless, this limitation doesn’t considerably scale back the risk, as many assault situations contain preliminary compromise by way of phishing, malware, or different vectors that present the required foothold.
CVEsAffected ProductsImpactExploit PrerequisitesCVSS 3.1 ScoreCVE-2025-27462 CVE-2025-27463 CVE-2025-27464XenServer VM Instruments for Home windows variations <9.4.1 (XenServer 8.4, Citrix Hypervisor 8.2 CU1 LTSR)Native privilege escalation to visitor kernel through XenCons driverAttacker should execute arbitrary unprivileged code in Home windows visitor VM8.8 (Excessive)
Mitigations
Citrix and XenServer have launched XenServer VM Instruments for Home windows model 9.4.1 to handle these vulnerabilities.
The up to date instruments include particular part variations, together with xenbus 9.1.11.115, xeniface 9.1.12.94, and different patched drivers.
Directors ought to instantly replace all Home windows VMs to the most recent XenServer VM Instruments model by way of a number of out there channels: direct obtain from Citrix assist, Home windows Replace mechanism, or the Administration Agent automated replace function.
Organizations utilizing Home windows Replace ought to confirm that “Handle Citrix PV drivers through Home windows Replace” is enabled.
For environments unable to instantly patch, a PowerShell mitigation script is on the market that may scan for vulnerabilities or apply non permanent fixes by inserting applicable safety descriptors into the registry.
Nevertheless, this script solely addresses the XenIface driver vulnerability and needs to be thought-about a brief measure.
Crucial infrastructure operators ought to prioritize these updates, as virtualized environments typically host mission-critical purposes and delicate knowledge programs.
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