Description
In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]
Affected products
linux: linux kernel
References5
- git.kernel.org/stable/c/009c0f726abeaa67aad1d96b883bdce01d405ce2 Patch
- git.kernel.org/stable/c/5fb4a5f361565f5b629d8a8fe5288ce8463c5727 Patch
- git.kernel.org/stable/c/924d721fae95687acedbaf624a094ed0e8b67104 Patch
- git.kernel.org/stable/c/c36991c6f8d2ab56ee67aff04e3c357f45cfc76c Patch
- git.kernel.org/stable/c/fcef67506c0234935cb0fb026740a637edb58d7c
Metrics
- CVSS 3.1
-
7.9
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H - EPSS — exploit probability
- 0% percentile: 3 · as of 14 November 2026
- CWE
- CWE-863
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