{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40266", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.183Z", "datePublished": "2025-12-04T16:08:25.392Z", "dateUpdated": "2026-08-05T12:09:01.305Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:09:01.305Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Check the untrusted offset in FF-A memory share\n\nVerify the offset to prevent OOB access in the hypervisor\nFF-A buffer in case an untrusted large enough value\n[U32_MAX - sizeof(struct ffa_composite_mem_region) + 1, U32_MAX]\nis set from the host kernel." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.2, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable code is the EL2 FF-A proxy, reached only via an SMC trapped from host EL1 with a host-supplied TX mailbox; this requires local execution on the machine, with no network or physical vector.\nAC:L - The host kernel fully controls the SMC registers (len/fraglen) and every byte of the TX buffer including composite_off, so the condition is set deterministically with no race or memory-layout dependency.\nPR:H - SMC is undefined at EL0 and no userspace FF-A interface exists, so the attacker must already execute code in the host kernel at EL1 — real root plus kernel-level access, not reachable through user namespaces.\nUI:N - The attacker issues the FFA_MEM_SHARE/FFA_MEM_LEND SMC itself; no victim action or interaction of any kind is needed.\nS:C - The vulnerable component is the pKVM EL2 hypervisor, a distinct security authority whose purpose is isolating protected guest VMs and the secure world from the untrusted host; corrupting it impacts resources beyond the host kernel's own authority.\nC:H - The out-of-bounds read extends far past the single-page hyp TX buffer with attacker-chosen displacement and unbounded length, and the OOB contents drive observable host-page sharing decisions, forming a disclosure oracle over hypervisor-private memory.\nI:H - Out-of-bounds constituent data is passed to __pkvm_host_share_ffa(), corrupting the hypervisor's page-ownership state and defeating the FF-A filter that prevents host-mediated exposure of protected guest memory to the secure world.\nA:H - Walking hundreds of millions of constituents past a one-page EL2 mapping faults in the hypervisor, causing hyp_panic and taking down the host and every guest on the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/kvm/hyp/nvhe/ffa.c" ], "versions": [ { "version": "6211753fdfd05af9e08f54c8d0ba3ee516034878", "lessThan": "fc3139d9f4c1fe1c7d5f25f99676bd8e9c6a1041", "status": "affected", "versionType": "git" }, { "version": "6211753fdfd05af9e08f54c8d0ba3ee516034878", "lessThan": "bc1909ef38788f2ee3d8011d70bf029948433051", "status": "affected", "versionType": "git" }, { "version": "6211753fdfd05af9e08f54c8d0ba3ee516034878", "lessThan": "f9f1aed6c8a3427900da3121e1868124854569c3", "status": "affected", "versionType": "git" }, { "version": "6211753fdfd05af9e08f54c8d0ba3ee516034878", "lessThan": "103e17aac09cdd358133f9e00998b75d6c1f1518", "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/kvm/hyp/nvhe/ffa.c" ], "versions": [ { "version": "3.11", "status": "affected" }, { "version": "0", "lessThan": "3.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.118", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.10", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "3.11", "versionEndExcluding": "6.6.118" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.12.60" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.17.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.11", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fc3139d9f4c1fe1c7d5f25f99676bd8e9c6a1041" }, { "url": "https://git.kernel.org/stable/c/bc1909ef38788f2ee3d8011d70bf029948433051" }, { "url": "https://git.kernel.org/stable/c/f9f1aed6c8a3427900da3121e1868124854569c3" }, { "url": "https://git.kernel.org/stable/c/103e17aac09cdd358133f9e00998b75d6c1f1518" } ], "title": "KVM: arm64: Check the untrusted offset in FF-A memory share", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T19:59:35.285244Z", "id": "CVE-2025-40266", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T19:59:44.078Z" } } ] } }