{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47200", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-03-25T09:12:14.117Z", "datePublished": "2024-04-10T18:56:35.152Z", "dateUpdated": "2026-08-05T08:46:41.297Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:46:41.297Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/prime: Fix use after free in mmap with drm_gem_ttm_mmap\n\ndrm_gem_ttm_mmap() drops a reference to the gem object on success. If\nthe gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that\ndrop will free the gem object, and the subsequent drm_gem_object_get()\nwill be a UAF. Fix by grabbing a reference before calling the mmap\nhelper.\n\nThis issue was forseen when the reference dropping was adding in\ncommit 9786b65bc61ac (\"drm/ttm: fix mmap refcounting\"):\n \"For that to work properly the drm_gem_object_get() call in\n drm_gem_ttm_mmap() must be moved so it happens before calling\n obj->funcs->mmap(), otherwise the gem refcount would go down\n to zero.\"" } ], "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 - Exploitation requires local access to a DRM render/primary node and userspace mmap of an exported dma-buf fd via ioctl/syscall paths, not remote packet processing.\nAC:L - The attacker fully controls the create/export/close/mmap sequence that leaves gem refcount at 1, so the UAF is triggered reliably with no race or victim-dependent state.\nPR:L - GEM create, PRIME export, and GEM close are available to unprivileged render clients (DRM_RENDER_ALLOW) on drivers such as amdgpu/nouveau; Android apps and desktop video/render-group users can open /dev/dri/renderD*.\nUI:N - The attacker performs all required DRM and mmap operations themselves; no action by another user is needed.\nS:U - Impact is confined to the local kernel/host security authority (standard local privilege escalation via DRM UAF), not a VM/IOMMU/sandbox boundary crossing.\nC:H - Use-after-free of a GEM/TTM object allows reclaim and reuse of the freed object, enabling arbitrary kernel memory disclosure primitives.\nI:H - The same UAF can be turned into heap corruption and write primitives for control-flow hijacking or arbitrary kernel writes.\nA:H - Dereferencing or refcounting the freed GEM object can oops/panic the kernel even without a full exploit chain." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/drm_prime.c" ], "versions": [ { "version": "9786b65bc61acec63f923978c75e707afbb74bc7", "lessThan": "4f8e469a2384dfa4047145b0093126462cbb6dc0", "status": "affected", "versionType": "git" }, { "version": "9786b65bc61acec63f923978c75e707afbb74bc7", "lessThan": "8244a3bc27b3efd057da154b8d7e414670d5044f", "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/gpu/drm/drm_prime.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.5", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16", "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": "5.5", "versionEndExcluding": "5.15.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.16" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4f8e469a2384dfa4047145b0093126462cbb6dc0" }, { "url": "https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f" } ], "title": "drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-04-15T14:57:54.210831Z", "id": "CVE-2021-47200", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-07-03T17:48:37.560Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:32:07.374Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/4f8e469a2384dfa4047145b0093126462cbb6dc0", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f", "tags": [ "x_transferred" ] } ] } ] } }