{"cve":"CVE-2022-49840","nvd":{"published":"2025-05-01T15:16:07.493","modified":"2026-06-17T05:19:16.330","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()\n\nWe got a syzkaller problem because of aarch64 alignment fault\nif KFENCE enabled. When the size from user bpf program is an odd\nnumber, like 399, 407, etc, it will cause the struct skb_shared_info's\nunaligned access. As seen below:\n\n  BUG: KFENCE: use-after-free read in __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032\n\n  Use-after-free read at 0xffff6254fffac077 (in kfence-#213):\n   __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:26 [inline]\n   arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline]\n   arch_atomic_inc include/linux/atomic-arch-fallback.h:270 [inline]\n   atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline]\n   __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032\n   skb_clone+0xf4/0x214 net/core/skbuff.c:1481\n   ____bpf_clone_redirect net/core/filter.c:2433 [inline]\n   bpf_clone_redirect+0x78/0x1c0 net/core/filter.c:2420\n   bpf_prog_d3839dd9068ceb51+0x80/0x330\n   bpf_dispatcher_nop_func include/linux/bpf.h:728 [inline]\n   bpf_test_run+0x3c0/0x6c0 net/bpf/test_run.c:53\n   bpf_prog_test_run_skb+0x638/0xa7c net/bpf/test_run.c:594\n   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]\n   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]\n   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381\n\n  kfence-#213: 0xffff6254fffac000-0xffff6254fffac196, size=407, cache=kmalloc-512\n\n  allocated by task 15074 on cpu 0 at 1342.585390s:\n   kmalloc include/linux/slab.h:568 [inline]\n   kzalloc include/linux/slab.h:675 [inline]\n   bpf_test_init.isra.0+0xac/0x290 net/bpf/test_run.c:191\n   bpf_prog_test_run_skb+0x11c/0xa7c net/bpf/test_run.c:512\n   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]\n   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]\n   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381\n   __arm64_sys_bpf+0x50/0x60 kernel/bpf/syscall.c:4381\n\nTo fix the problem, we adjust @size so that (@size + @hearoom) is a\nmultiple of SMP_CACHE_BYTES. So we make sure the struct skb_shared_info\nis aligned to a cache line.","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/047824a730699c6c66df43306b80f700c9dfc2fd","https://git.kernel.org/stable/c/1b597f2d6a55e9f549989913860ad5170da04964","https://git.kernel.org/stable/c/730fb1ef974a13915bc7651364d8b3318891cd70","https://git.kernel.org/stable/c/7a704dbfd3735304e261f2787c52fbc7c3884736","https://git.kernel.org/stable/c/d3fd203f36d46aa29600a72d57a1b61af80e4a25"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:01:22.920403922+00:00"},"epss":{"cve":"CVE-2022-49840","score":0.00223,"percentile":0.12986,"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."]}