{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-42235", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-07-30T07:40:12.252Z", "datePublished": "2024-08-07T15:14:25.070Z", "dateUpdated": "2026-08-05T11:36:00.433Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:36:00.433Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/mm: Add NULL pointer check to crst_table_free() base_crst_free()\n\ncrst_table_free() used to work with NULL pointers before the conversion\nto ptdescs. Since crst_table_free() can be called with a NULL pointer\n(error handling in crst_table_upgrade() add an explicit check.\n\nAlso add the same check to base_crst_free() for consistency reasons.\n\nIn real life this should not happen, since order two GFP_KERNEL\nallocations will not fail, unless FAIL_PAGE_ALLOC is enabled and used." } ], "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 path is entered only through a local `mmap()`/`mremap()`/`shmat()` syscall on s390, via `arch_get_unmapped_area()` → `check_asce_limit()` → `crst_table_upgrade()`. No network, adjacent-network, or remote-peer data reaches this code.\nAC:L - The attacker fully controls the address-space geometry needed (two ordinary high-address mmaps drive `asce_limit` to `_REGION1_SIZE` and then request a 5-level upgrade, leaving `p4d == NULL`), and can engineer the required order-2 `GFP_KERNEL` failure by driving their own multithreaded process into the OOM-victim state that makes `__alloc_pages_slowpath()` return NULL, retrying as often as needed. Every attempt is cheap and repeatable, so the remaining timing window is one the attacker creates rather than one beyond their control.\nPR:L - Any unprivileged local user can call `mmap()` with a high address hint — there is no capability check, namespace requirement, or privileged device node anywhere between the syscall entry and `crst_table_free()`. On IBM Z / LinuxONE hosts this means any shared-tenant, container, or shell user.\nUI:N - The whole sequence is performed by the attacking process itself through ordinary syscalls; no victim must mount a filesystem, open a device, or take any other action.\nS:U - The corrupted page-allocator state and the freed reserved page remain entirely within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - On 6.6.y the reserved PFN 0 (the s390 absolute-zero lowcore holding restart PSWs and `restart_fn`/`restart_data` kernel pointers plus machine-check save areas) is released into the buddy allocator with the sanity checks compiled out, so it can be handed to an attacker-influenced allocation still containing that firmware/kernel state; repeating the trigger underflows the refcount of whatever page then occupies PFN 0, yielding a use-after-free read primitive over live kernel memory.\nI:H - Injecting a memblock-reserved page into the buddy free lists breaks the allocator's ownership invariant — the page is concurrently written by hardware/firmware (store status, machine-check save area) while owned by another kernel object or user mapping — and the refcount underflow on repeat triggers gives a double-free/page-reuse primitive, the classic route to controlled kernel writes.\nA:H - On 6.9/6.10 the underflowed `__pa(0)` produces a wild `struct page *` that faults in `compound_order()`, oopsing the kernel; on 6.6.y with page-checking enabled it produces a \"BUG: Bad page state\" splat and `TAINT_BAD_PAGE` (a panic under `panic_on_taint`), and with checks off the corrupted allocator state leads to subsequent oops/panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/s390/mm/pgalloc.c" ], "versions": [ { "version": "6326c26c1514757242829b292b26eac589013200", "lessThan": "794fa52b94637d6b2e8c9474fbe3983af5c9f046", "status": "affected", "versionType": "git" }, { "version": "6326c26c1514757242829b292b26eac589013200", "lessThan": "f80bd8bb6f380bc265834c46058d38b34174813e", "status": "affected", "versionType": "git" }, { "version": "6326c26c1514757242829b292b26eac589013200", "lessThan": "b5efb63acf7bddaf20eacfcac654c25c446eabe8", "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/s390/mm/pgalloc.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.41", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9.10", "lessThanOrEqual": "6.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10", "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": "6.6", "versionEndExcluding": "6.6.41" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.9.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.10" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/794fa52b94637d6b2e8c9474fbe3983af5c9f046" }, { "url": "https://git.kernel.org/stable/c/f80bd8bb6f380bc265834c46058d38b34174813e" }, { "url": "https://git.kernel.org/stable/c/b5efb63acf7bddaf20eacfcac654c25c446eabe8" } ], "title": "s390/mm: Add NULL pointer check to crst_table_free() base_crst_free()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-42235", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T16:14:07.518719Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-11T17:34:32.266Z" } } ] } }