{"cve":"CVE-2025-21851","nvd":{"published":"2025-03-12T10:15:17.703","modified":"2026-07-30T06:21:41.180","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix softlockup in arena_map_free on 64k page kernel\n\nOn an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y,\narena_htab tests cause a segmentation fault and soft lockup.\nThe same failure is not observed with 4k pages on aarch64.\n\nIt turns out arena_map_free() is calling\napply_to_existing_page_range() with the address returned by\nbpf_arena_get_kern_vm_start().  If this address is not page-aligned\nthe code ends up calling apply_to_pte_range() with that unaligned\naddress causing soft lockup.\n\nFix it by round up GUARD_SZ to PAGE_SIZE << 1 so that the\ndivision by 2 in bpf_arena_get_kern_vm_start() returns\na page-aligned value.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":3.3},"cwes":["CWE-667"],"references":["https://git.kernel.org/stable/c/517e8a7835e8cfb398a0aeb0133de50e31cae32b","https://git.kernel.org/stable/c/787d556a3de447e70964a4bdeba9196f62a62b1e","https://git.kernel.org/stable/c/c1f3f3892d4526f18aaeffdb6068ce861e793ee3"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:00:17.429720821+00:00"},"epss":{"cve":"CVE-2025-21851","score":0.00177,"percentile":0.07246,"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."]}