Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:HSummary
CVE-2023-46842 is a medium-severity Type Confusion (CWE-843) vulnerability in Fedoraproject Fedora. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
The vulnerability is a denial-of-service issue in the Xen hypervisor (XSA-454) affecting HVM guests. Unlike 32-bit PV guests, HVM guests can freely switch between 64-bit and other modes and therefore place out-of-range values in registers used to pass 32-bit hypercall arguments. When a long-running hypercall triggers a continuation, the hypervisor performs internal sanity checks on translated register values that incorrectly assume the high halves are always clear; violation of this assumption causes a hypervisor consistency check and crash.
A local attacker with a running HVM guest can exploit the flaw by arranging for a time-consuming hypercall while registers contain unexpected high-half values. Successful exploitation results in a hypervisor crash, producing a host-wide availability impact (CVSS 6.5) without requiring elevated privileges inside the guest or user interaction.
Advisories published by the Xen Project (XSA-454) and downstream distributions such as Fedora describe the issue and point to updated hypervisor packages that correct the register-value handling during hypercall continuation.
EPSS for the CVE rose from a low baseline to a peak of 0.0731 on 2025-12-11 before receding, indicating measurable post-disclosure exploitation interest.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-51008
Vulnerability Data
Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and other modes. This in particular means that they may set registers used to pass 32-bit-mode hypercall arguments to values outside of the range 32-bit code would be able…
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to set them to. When processing of hypercalls takes a considerable amount of time, the hypervisor may choose to invoke a hypercall continuation. Doing so involves putting (perhaps updated) hypercall arguments in respective registers. For guests not running in 64-bit mode this further involves a certain amount of translation of the values. Unfortunately internal sanity checking of these translated values assumes high halves of registers to always be clear when invoking a hypercall. When this is found not to be the case, it triggers a consistency check in the hypervisor and causes a crash.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including fuzzing and type-aware analysis) directly finds type-confusion flaws before deployment.
Engineering principles can require use of type-safe languages, static typing, and runtime type checks that structurally avoid allocating one type and accessing another.
Memory-protection controls limit the blast radius when a type-confusion access occurs but do not stop the flaw itself.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent type-confusion flaws via safe typing, static analysis, and code review while the control itself addresses many additional weaknesses.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect type-confusion vulnerabilities through fuzzing and static analysis.
Secure SDLC mandates type-safe design and review that can catch type-confusion flaws.
Application security requirements can specify strong typing and interface contracts that reduce type confusion.
Secure architecture principles promote type-safe languages and memory-safety mechanisms that mitigate type confusion.
Secure coding standards directly forbid unsafe type casts and require static-analysis checks for type confusion.