{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-43832","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-08-17T09:11:59.273Z","datePublished":"2024-08-17T09:21:50.230Z","dateUpdated":"2026-08-05T11:36:41.646Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:36:41.646Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/uv: Don't call folio_wait_writeback() without a folio reference\n\nfolio_wait_writeback() requires that no spinlocks are held and that\na folio reference is held, as documented. After we dropped the PTL, the\nfolio could get freed concurrently. So grab a temporary reference."}],"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 through the s390 KVM protected-virtualization path — the `KVM_S390_PV_COMMAND`/`KVM_RUN` ioctls on /dev/kvm and the host's secure/non-secure storage-access fault handler running in the vCPU thread. No network input is involved, so local system access is required.\nAC:L - The attacker controls both sides of the race: it forces `rc == -EAGAIN` deterministically (start writeback on the file/shmem-backed guest page so `make_folio_secure()` returns -EAGAIN, or hold the folio lock) while a second thread `MADV_DONTNEED`s/munmaps that guest memory to free the folio in the window after the PTL and mmap_read_lock are dropped. The attempt is cheap and infinitely retryable.\nPR:L - Only an unprivileged local user with access to /dev/kvm (commonly mode 0666 or the `kvm` group on distros) is needed to create a VM, enable protected virtualization, and drive the unpack/secure-storage paths; no CAP_SYS_ADMIN or real root is required. A malicious guest reaching `handle_pv_uvc()` with a guest-controlled address is likewise not a privileged host actor.\nUI:N - The entire sequence is performed by the attacker's own threads via ioctls and memory-management syscalls on its own VM. No victim action of any kind is needed.\nS:U - The attacking process and the corrupted resources (host kernel MM metadata) live under the same security authority — this is a local host-kernel compromise, not an IOMMU or hypervisor-boundary escape granting control of a separate authority.\nC:H - This is a use-after-free on a folio whose `struct page` has been reallocated to an unrelated owner; the code reads that stale state and the resulting page-state corruption is leverageable for disclosure of memory belonging to other subsystems. Per UAF scoring guidance, confidentiality impact is High.\nI:H - `folio_wait_bit_common()` performs an atomic `set_bit(PG_waiters, &folio->flags)` write into a `struct page` that now describes someone else's allocation, corrupting core MM metadata for a page the attacker can influence the reuse of via heap/page grooming — a write primitive into kernel state, hence High.\nA:H - A stale `PG_writeback` bit in the reused page makes `folio_wait_bit()` sleep TASK_UNINTERRUPTIBLE with no waker, producing an unkillable task and hung-task panics, while a spurious `PG_waiters` trips `bad_page()` (\"BUG: Bad page state\") since `PAGE_FLAGS_CHECK_AT_PREP` covers the whole flags mask. Either outcome is a full kernel-level denial of service."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/s390/kernel/uv.c"],"versions":[{"version":"214d9bbcd3a67230b932f6cea83c078ab34d9e70","lessThan":"1a1eb2f3fc453dcd52726d13e863938561489cb7","status":"affected","versionType":"git"},{"version":"214d9bbcd3a67230b932f6cea83c078ab34d9e70","lessThan":"8736604ef53359a718c246087cd21dcec232d2fb","status":"affected","versionType":"git"},{"version":"214d9bbcd3a67230b932f6cea83c078ab34d9e70","lessThan":"b21aba72aadd94bdac275deab021fc84d6c72b16","status":"affected","versionType":"git"},{"version":"214d9bbcd3a67230b932f6cea83c078ab34d9e70","lessThan":"3f29f6537f54d74e64bac0a390fb2e26da25800d","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/kernel/uv.c"],"versions":[{"version":"5.7","status":"affected"},{"version":"0","lessThan":"5.7","status":"unaffected","versionType":"semver"},{"version":"6.1.103","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.44","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.10.3","lessThanOrEqual":"6.10.*","status":"unaffected","versionType":"semver"},{"version":"6.11","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":"5.7","versionEndExcluding":"6.1.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.6.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.10.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.11"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1a1eb2f3fc453dcd52726d13e863938561489cb7"},{"url":"https://git.kernel.org/stable/c/8736604ef53359a718c246087cd21dcec232d2fb"},{"url":"https://git.kernel.org/stable/c/b21aba72aadd94bdac275deab021fc84d6c72b16"},{"url":"https://git.kernel.org/stable/c/3f29f6537f54d74e64bac0a390fb2e26da25800d"}],"title":"s390/uv: Don't call folio_wait_writeback() without a folio reference","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-43832","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T16:08:24.816195Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-09-12T17:33:07.778Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T22:05:16.929Z"}}]}}