{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-22013", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.806Z", "datePublished": "2025-04-08T08:18:04.000Z", "dateUpdated": "2026-08-05T11:55:59.327Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:59.327Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state\n\nThere are several problems with the way hyp code lazily saves the host's\nFPSIMD/SVE state, including:\n\n* Host SVE being discarded unexpectedly due to inconsistent\n configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to\n result in QEMU crashes where SVE is used by memmove(), as reported by\n Eric Auger:\n\n https://issues.redhat.com/browse/RHEL-68997\n\n* Host SVE state is discarded *after* modification by ptrace, which was an\n unintentional ptrace ABI change introduced with lazy discarding of SVE state.\n\n* The host FPMR value can be discarded when running a non-protected VM,\n where FPMR support is not exposed to a VM, and that VM uses\n FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR\n before unbinding the host's FPSIMD/SVE/SME state, leaving a stale\n value in memory.\n\nAvoid these by eagerly saving and \"flushing\" the host's FPSIMD/SVE/SME\nstate when loading a vCPU such that KVM does not need to save any of the\nhost's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is\nremoved and the necessary call to fpsimd_save_and_flush_cpu_state() is\nplaced in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr'\nshould not be used, they are set to NULL; all uses of these will be\nremoved in subsequent patches.\n\nHistorical problems go back at least as far as v5.17, e.g. erroneous\nassumptions about TIF_SVE being clear in commit:\n\n 8383741ab2e773a9 (\"KVM: arm64: Get rid of host SVE tracking/saving\")\n\n... and so this eager save+flush probably needs to be backported to ALL\nstable trees." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H", "baseScore": 7.3, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is `kvm_arch_vcpu_load_fp()`/`kvm_arch_vcpu_put_fp()`, reached only through the `KVM_RUN` ioctl on `/dev/kvm` from a local process on the host. No network or adjacent-network input reaches this code.\nAC:L - The attacker deterministically controls every condition: enabling SVE in its own thread, issuing `KVM_RUN` with a guest that never touches FP/SIMD (so `guest_owns_fp_regs()` is false and no flush occurs), and then executing SVE code after return. CONFIG_ARM64_SVE is default-y and SVE-capable hardware (ARMv9, Neoverse V1/V2, Graviton 3/4, Ampere) is mainstream.\nPR:L - Only an unprivileged local account with access to `/dev/kvm` is needed — systemd's default udev rule installs it as `MODE=\"0666\"`, and Android AVF/ChromeOS crosvm expose VM creation to unprivileged apps. No root, CAP_SYS_ADMIN, or init-namespace capability is required.\nUI:N - The attacking process performs the entire sequence itself — set up SVE, call `KVM_RUN`, return, run SVE code — with no action by any other user or administrator.\nS:U - The mismanaged FPSIMD/SVE/SME context belongs to the same host task that invoked `KVM_RUN`, and the kernel remains the single security authority over both the vulnerable KVM/fpsimd code and the impacted host process; this is not a guest-to-host escape or an IOMMU bypass.\nC:L - `fpsimd_kvm_prepare()` populates `uw.fpsimd_state` from the stale in-memory `thread.sve_state` while the live values sit in registers, so a stale register snapshot can resurface in signal frames/core dumps, and SVE-accelerated string/memory routines running with silently discarded vector state can process and emit unintended buffer contents — a bounded, indirect disclosure rather than arbitrary memory read.\nI:H - Host SVE/FPMR register state is silently corrupted mid-computation outside any ABI-sanctioned discard point, so SVE-based `memmove()`/`memcpy()` in glibc write wrong data into arbitrary destinations, producing memory corruption inside the affected process (the observed QEMU failures); it also silently drops SVE register values written via ptrace, breaking the debugger/CRIU ABI.\nA:H - The corruption reliably crashes the affected process — the reported real-world symptom is QEMU aborting when SVE-based `memmove()` copies garbage — killing the VM and its workload, and it can be re-triggered at will by any local user with `/dev/kvm`." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/kernel/fpsimd.c", "arch/arm64/kvm/fpsimd.c" ], "versions": [ { "version": "c4ab60a86c5ed7c0d727c6dc8cec352e16bc7f90", "lessThan": "5289ac43b69c61a49c75720921f2008005a31c43", "status": "affected", "versionType": "git" }, { "version": "d5f7d3833b534f9e43e548461dba1e60aa82f587", "lessThan": "04c50cc23a492c4d43fdaefc7c1ecc0ff6f7b82e", "status": "affected", "versionType": "git" }, { "version": "93ae6b01bafee8fa385aa25ee7ebdb40057f6abe", "lessThan": "806d5c1e1d2e5502175a24bf70f251648d99c36a", "status": "affected", "versionType": "git" }, { "version": "93ae6b01bafee8fa385aa25ee7ebdb40057f6abe", "lessThan": "79e140bba70bcacc5fe15bf8c0b958793fd7d56f", "status": "affected", "versionType": "git" }, { "version": "93ae6b01bafee8fa385aa25ee7ebdb40057f6abe", "lessThan": "900b444be493b7f404898c785d6605b177a093d0", "status": "affected", "versionType": "git" }, { "version": "93ae6b01bafee8fa385aa25ee7ebdb40057f6abe", "lessThan": "fbc7e61195e23f744814e78524b73b59faa54ab4", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/kernel/fpsimd.c", "arch/arm64/kvm/fpsimd.c" ], "versions": [ { "version": "6.2", "status": "affected" }, { "version": "0", "lessThan": "6.2", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.85", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.21", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.9", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.85" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.13.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5289ac43b69c61a49c75720921f2008005a31c43" }, { "url": "https://git.kernel.org/stable/c/04c50cc23a492c4d43fdaefc7c1ecc0ff6f7b82e" }, { "url": "https://git.kernel.org/stable/c/806d5c1e1d2e5502175a24bf70f251648d99c36a" }, { "url": "https://git.kernel.org/stable/c/79e140bba70bcacc5fe15bf8c0b958793fd7d56f" }, { "url": "https://git.kernel.org/stable/c/900b444be493b7f404898c785d6605b177a093d0" }, { "url": "https://git.kernel.org/stable/c/fbc7e61195e23f744814e78524b73b59faa54ab4" } ], "title": "KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state", "x_generator": { "engine": "bippy-1.2.0" } } } }