{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38595", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.028Z", "datePublished": "2025-08-19T17:03:25.527Z", "dateUpdated": "2026-08-05T12:03:17.183Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:03:17.183Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen: fix UAF in dmabuf_exp_from_pages()\n\n[dma_buf_fd() fixes; no preferences regarding the tree it goes through -\nup to xen folks]\n\nAs soon as we'd inserted a file reference into descriptor table, another\nthread could close it. That's fine for the case when all we are doing is\nreturning that descriptor to userland (it's a race, but it's a userland\nrace and there's nothing the kernel can do about it). However, if we\nfollow fd_install() with any kind of access to objects that would be\ndestroyed on close (be it the struct file itself or anything destroyed\nby its ->release()), we have a UAF.\n\ndma_buf_fd() is a combination of reserving a descriptor and fd_install().\ngntdev dmabuf_exp_from_pages() calls it and then proceeds to access the\nobjects destroyed on close - starting with gntdev_dmabuf itself.\n\nFix that by doing reserving descriptor before anything else and do\nfd_install() only when everything had been set up." } ], "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 vulnerability is reached through `IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS` on the local `/dev/xen/gntdev` misc device, requiring local access to the machine (dom0 or a HVM/PVH guest). No network-facing path reaches `dmabuf_exp_from_pages()`.\nAC:L - The attacker controls both sides of the race — one thread issues the export ioctl while another closes the freshly installed fd, whose number is deterministic (lowest free descriptor) — and the window spans a sleepable `mutex_lock()`, making it wide; the ioctl can be retried indefinitely until it wins.\nPR:L - `gntdev_ioctl()` contains no `capable()` or `CAP_*` checks at all, so any user able to open `/dev/xen/gntdev` can trigger it; Xen stacks that use this exact dma-buf path (automotive display virtualization, Qubes vchan) grant unprivileged users access to that node.\nUI:N - Exploitation is entirely self-contained within the attacker's own multi-threaded process issuing an ioctl and a concurrent `close()`; no victim action is required.\nS:U - The freed objects (`struct gntdev_dmabuf`, the gntdev `struct file`) and the resulting corruption all live in the same kernel's memory as the attacker's own domain; nothing crosses the hypervisor or IOMMU boundary.\nC:H - `get_file(gntdev_dmabuf->priv->filp)` reads a pointer out of freed, attacker-groomable `kmalloc-96` memory, and `list_add()` writes kernel heap pointers into that freed slot which can be read back via a resprayed object, yielding kernel memory disclosure; the resulting `struct file` UAF permits arbitrary kernel read.\nI:H - The unmatched `fput()` on `priv->filp` underflows the gntdev file refcount and frees a `struct file` still referenced by an open fd, and the code writes into the freed `gntdev_dmabuf` (`->fd = ret`, `list_add`) — a classic UAF/DirtyCred-style write primitive leading to control-flow hijack and privilege escalation.\nA:H - Losing the race before `list_add()` makes `dmabuf_exp_release()` run `list_del()` on a zeroed `list_head`, causing a NULL-pointer write oops (or a corruption WARN plus heap/list corruption), and the general UAF and file refcount underflow readily panic the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/xen/gntdev-dmabuf.c" ], "versions": [ { "version": "a240d6e42e28c34fdc34b3a98ca838a31c939901", "lessThan": "e5907885260401bba300d4d18d79875c05b82651", "status": "affected", "versionType": "git" }, { "version": "a240d6e42e28c34fdc34b3a98ca838a31c939901", "lessThan": "3edfd2353f301bfffd5ee41066e37320a59ccc2d", "status": "affected", "versionType": "git" }, { "version": "a240d6e42e28c34fdc34b3a98ca838a31c939901", "lessThan": "d59d49af4aeed9a81e673e37c26c6a3bacf1a181", "status": "affected", "versionType": "git" }, { "version": "a240d6e42e28c34fdc34b3a98ca838a31c939901", "lessThan": "532c8b51b3a8676cbf533a291f8156774f30ea87", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/xen/gntdev-dmabuf.c" ], "versions": [ { "version": "4.19", "status": "affected" }, { "version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.42", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.10", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.1", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "4.19", "versionEndExcluding": "6.12.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.15.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.16.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e5907885260401bba300d4d18d79875c05b82651" }, { "url": "https://git.kernel.org/stable/c/3edfd2353f301bfffd5ee41066e37320a59ccc2d" }, { "url": "https://git.kernel.org/stable/c/d59d49af4aeed9a81e673e37c26c6a3bacf1a181" }, { "url": "https://git.kernel.org/stable/c/532c8b51b3a8676cbf533a291f8156774f30ea87" } ], "title": "xen: fix UAF in dmabuf_exp_from_pages()", "x_generator": { "engine": "bippy-1.2.0" } } } }