{ "dataType": "CVE_RECORD", "cveMetadata": { "cveId": "CVE-2024-35791", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-17T12:19:12.339Z", "datePublished": "2024-05-17T12:24:49.520Z", "dateUpdated": "2026-08-05T11:29:57.222Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:29:57.222Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()\n\nDo the cache flush of converted pages in svm_register_enc_region() before\ndropping kvm->lock to fix use-after-free issues where region and/or its\narray of pages could be freed by a different task, e.g. if userspace has\n__unregister_enc_region_locked() already queued up for the region.\n\nNote, the \"obvious\" alternative of using local variables doesn't fully\nresolve the bug, as region->pages is also dynamically allocated. I.e. the\nregion structure itself would be fine, but region->pages could be freed.\n\nFlushing multiple pages under kvm->lock is unfortunate, but the entire\nflow is a rare slow path, and the manual flush is only needed on CPUs that\nlack coherency for encrypted memory." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable code is reached only through the `KVM_MEMORY_ENCRYPT_REG_REGION`/`KVM_MEMORY_ENCRYPT_UNREG_REGION` ioctls on a local KVM VM file descriptor obtained from /dev/kvm. There is no remote or network-facing path to `sev_mem_enc_register_region()`.\nAC:L - The attacker controls both sides of the race, issuing the register and unregister ioctls from two threads it owns, and can widen the window arbitrarily by registering a large region since `sev_clflush_pages()` loops per page with `cond_resched()` after the lock is dropped. Nothing about winning the race depends on conditions outside the attacker's influence.\nPR:L - No capability check exists on the path — neither `kvm_arch_vm_ioctl()`'s `KVM_MEMORY_ENCRYPT_*_REGION` cases nor `sev_guest_init()` require CAP_SYS_ADMIN — so any local user with access to /dev/kvm (commonly granted via the `kvm` group or permissive device modes on virtualization hosts) can create an SEV VM and trigger the UAF.\nUI:N - The attacking process performs both ioctls itself; no action by any other user or victim process is needed.\nS:U - The attacker is host userspace (the VMM process) corrupting host kernel memory, so the vulnerable component and impacted component share the same security authority. This is not a guest-to-host escape, as the guest cannot issue these ioctls.\nC:H - The use-after-free reads a freed, sprayable kvmalloc'd `struct page *` array and then maps and flushes those attacker-influenceable pointers via `kmap_local_page()`, exposing arbitrary kernel/physical memory and enabling information disclosure once the freed slabs are reallocated.\nI:H - Two heap objects (`region` and `region->pages`) are used after being freed and can be reallocated with attacker-controlled contents, giving the heap-spray primitives typical of exploitable UAFs; `clflush_cache_range()` on a bogus mapping additionally acts on memory outside the intended range.\nA:H - Dereferencing freed `region->npages`/`region->pages` and calling `kmap_local_page()` on garbage `struct page` pointers reliably produces an oops or panic, taking the host kernel down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/sev.c" ], "versions": [ { "version": "4f627ecde7329e476a077bb0590db8f27bb8f912", "lessThan": "2d13b79640b147bd77c34a5998533b2021a4122d", "status": "affected", "versionType": "git" }, { "version": "19a23da53932bc8011220bd8c410cb76012de004", "lessThan": "e126b508ed2e616d679d85fca2fbe77bb48bbdd7", "status": "affected", "versionType": "git" }, { "version": "19a23da53932bc8011220bd8c410cb76012de004", "lessThan": "4868c0ecdb6cfde7c70cf478c46e06bb9c7e5865", "status": "affected", "versionType": "git" }, { "version": "19a23da53932bc8011220bd8c410cb76012de004", "lessThan": "12f8e32a5a389a5d58afc67728c76e61beee1ad4", "status": "affected", "versionType": "git" }, { "version": "19a23da53932bc8011220bd8c410cb76012de004", "lessThan": "f6d53d8a2617dd58c89171a6b9610c470ebda38a", "status": "affected", "versionType": "git" }, { "version": "19a23da53932bc8011220bd8c410cb76012de004", "lessThan": "5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807", "status": "affected", "versionType": "git" }, { "version": "f1ecde00ce1694597f923f0d25f7a797c5243d99", "status": "affected", "versionType": "git" }, { "version": "848bcb0a1d96f67d075465667d3a1ad4af56311e", "status": "affected", "versionType": "git" }, { "version": "5.10.15", "lessThan": "5.10.215", "status": "affected", "versionType": "semver" }, { "version": "4.19.176", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.98", "lessThan": "5.5", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/x86/kvm/svm/sev.c" ], "versions": [ { "version": "5.11", "status": "affected" }, { "version": "0", "lessThan": "5.11", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.215", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.154", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.84", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.24", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.12", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8", "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": "5.10.15", "versionEndExcluding": "5.10.215" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "6.1.84" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "6.6.24" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "6.7.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "6.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.98" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2d13b79640b147bd77c34a5998533b2021a4122d" }, { "url": "https://git.kernel.org/stable/c/e126b508ed2e616d679d85fca2fbe77bb48bbdd7" 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