{"cve":"CVE-2025-38185","nvd":{"published":"2025-07-04T14:15:25.377","modified":"2026-06-17T09:16:20.713","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\natm: atmtcp: Free invalid length skb in atmtcp_c_send().\n\nsyzbot reported the splat below. [0]\n\nvcc_sendmsg() copies data passed from userspace to skb and passes\nit to vcc->dev->ops->send().\n\natmtcp_c_send() accesses skb->data as struct atmtcp_hdr after\nchecking if skb->len is 0, but it's not enough.\n\nAlso, when skb->len == 0, skb and sk (vcc) were leaked because\ndev_kfree_skb() is not called and sk_wmem_alloc adjustment is missing\nto revert atm_account_tx() in vcc_sendmsg(), which is expected\nto be done in atm_pop_raw().\n\nLet's properly free skb with an invalid length in atmtcp_c_send().\n\n[0]:\nBUG: KMSAN: uninit-value in atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294\n atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294\n vcc_sendmsg+0xd7c/0xff0 net/atm/common.c:644\n sock_sendmsg_nosec net/socket.c:712 [inline]\n __sock_sendmsg+0x330/0x3d0 net/socket.c:727\n ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566\n ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620\n __sys_sendmsg net/socket.c:2652 [inline]\n __do_sys_sendmsg net/socket.c:2657 [inline]\n __se_sys_sendmsg net/socket.c:2655 [inline]\n __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655\n x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nUninit was created at:\n slab_post_alloc_hook mm/slub.c:4154 [inline]\n slab_alloc_node mm/slub.c:4197 [inline]\n kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4249\n kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579\n __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670\n alloc_skb include/linux/skbuff.h:1336 [inline]\n vcc_sendmsg+0xb40/0xff0 net/atm/common.c:628\n sock_sendmsg_nosec net/socket.c:712 [inline]\n __sock_sendmsg+0x330/0x3d0 net/socket.c:727\n ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566\n ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620\n __sys_sendmsg net/socket.c:2652 [inline]\n __do_sys_sendmsg net/socket.c:2657 [inline]\n __se_sys_sendmsg net/socket.c:2655 [inline]\n __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655\n x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCPU: 1 UID: 0 PID: 5798 Comm: syz-executor192 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(undef)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025","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:H","score":5.5},"cwes":["CWE-401"],"references":["https://git.kernel.org/stable/c/1b0ad18704913c92a3ad53748fbc0f219a75b876","https://git.kernel.org/stable/c/2f370ae1fb6317985f3497b1bb80d457508ca2f7","https://git.kernel.org/stable/c/3261c017a7c5d2815c6a388c5a3280d1fba0e8db","https://git.kernel.org/stable/c/a4b0fd8c25a7583f8564af6cc910418fb8954e89","https://git.kernel.org/stable/c/c19c0943424b412a84fdf178e6c71fe5480e4f0f"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:04:28.436527499+00:00"},"epss":{"cve":"CVE-2025-38185","score":0.00196,"percentile":0.0938,"date":"2026-11-01"},"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."]}