{"cve":"CVE-2023-54172","nvd":{"published":"2025-12-30T13:16:05.050","modified":"2026-06-17T06:46:56.200","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction\n\nOn hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs\nwith ConfigVersion 9.3 or later support IBT in the guest. However,\ncurrent versions of Hyper-V have a bug in that there's not an ENDBR64\ninstruction at the beginning of the hypercall page. Since hypercalls are\nmade with an indirect call to the hypercall page, all hypercall attempts\nfail with an exception and Linux panics.\n\nA Hyper-V fix is in progress to add ENDBR64. But guard against the Linux\npanic by clearing X86_FEATURE_IBT if the hypercall page doesn't start\nwith ENDBR. The VM will boot and run without IBT.\n\nIf future Linux 32-bit kernels were to support IBT, additional hypercall\npage hackery would be needed to make IBT work for such kernels in a\nHyper-V VM.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/73626b70b361ddda7c380e52c236aa4f2487c402","https://git.kernel.org/stable/c/98cccbd0a19a161971bc7f7feb10577adc62c400","https://git.kernel.org/stable/c/d5ace2a776442d80674eff9ed42e737f7dd95056"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:18:08.089039631+00:00"},"epss":{"cve":"CVE-2023-54172","score":0.00197,"percentile":0.0949,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}