{"cve":"CVE-2021-47200","nvd":{"published":"2024-04-10T19:15:48.077","modified":"2026-08-04T10:16:52.237","status":"Modified","description":"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.\"","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/4f8e469a2384dfa4047145b0093126462cbb6dc0","https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f","https://git.kernel.org/stable/c/4f8e469a2384dfa4047145b0093126462cbb6dc0","https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:48:32.179249784+00:00"},"epss":{"cve":"CVE-2021-47200","score":0.00221,"percentile":0.12738,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}