atm: atmtcp: Free invalid length skb in atmtcp_c_send().
syzbot reported the splat below. [0]
vcc_sendmsg() copies data passed from userspace to skb and passes
it to vcc->dev->ops->send().
atmtcp_c_send() accesses skb->data as struct atmtcp_hdr after
checking if skb->len is 0, but it's not enough.
Also, when skb->len == 0, skb and sk (vcc) were leaked because
dev_kfree_skb() is not called and sk_wmem_alloc adjustment is missing
to revert atm_account_tx() in vcc_sendmsg(), which is expected
to be done in atm_pop_raw().
Let's properly free skb with an invalid length in atmtcp_c_send().
[0]:
BUG: KMSAN: uninit-value in atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294
atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294
vcc_sendmsg+0xd7c/0xff0 net/atm/common.c:644
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x330/0x3d0 net/socket.c:727
____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566
___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
__sys_sendmsg net/socket.c:2652 [inline]
__do_sys_sendmsg net/socket.c:2657 [inline]
__se_sys_sendmsg net/socket.c:2655 [inline]
__x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655
x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was created at:
slab_post_alloc_hook mm/slub.c:4154 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4249
kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579
__alloc_skb+0x347/0x7d0 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1336 [inline]
vcc_sendmsg+0xb40/0xff0 net/atm/common.c:628
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x330/0x3d0 net/socket.c:727
____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566
___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
__sys_sendmsg net/socket.c:2652 [inline]
__do_sys_sendmsg net/socket.c:2657 [inline]
__se_sys_sendmsg net/socket.c:2655 [inline]
__x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655
x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
CPU: 1 UID: 0 PID: 5798 Comm: syz-executor192 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(undef)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4327-1 | linux security update |
Debian DLA |
DLA-4328-1 | linux-6.1 security update |
Debian DSA |
DSA-5973-1 | linux security update |
EUVD |
EUVD-2025-20071 | In the Linux kernel, the following vulnerability has been resolved: atm: atmtcp: Free invalid length skb in atmtcp_c_send(). syzbot reported the splat below. [0] vcc_sendmsg() copies data passed from userspace to skb and passes it to vcc->dev->ops->send(). atmtcp_c_send() accesses skb->data as struct atmtcp_hdr after checking if skb->len is 0, but it's not enough. Also, when skb->len == 0, skb and sk (vcc) were leaked because dev_kfree_skb() is not called and sk_wmem_alloc adjustment is missing to revert atm_account_tx() in vcc_sendmsg(), which is expected to be done in atm_pop_raw(). Let's properly free skb with an invalid length in atmtcp_c_send(). [0]: BUG: KMSAN: uninit-value in atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294 atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294 vcc_sendmsg+0xd7c/0xff0 net/atm/common.c:644 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4154 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4249 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1336 [inline] vcc_sendmsg+0xb40/0xff0 net/atm/common.c:628 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 5798 Comm: syz-executor192 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 |
Ubuntu USN |
USN-7856-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-8028-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8028-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8031-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8028-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8028-4 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8031-2 | Linux kernel (GCP FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-6 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-8031-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8052-1 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-8028-7 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8028-8 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-8052-2 | Linux kernel (Xilinx) vulnerabilities |
Ubuntu USN |
USN-8074-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8074-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
Thu, 18 Dec 2025 17:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux |
|
| Weaknesses | CWE-401 | |
| CPEs | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux |
Mon, 03 Nov 2025 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Sun, 06 Jul 2025 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Fri, 04 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: atm: atmtcp: Free invalid length skb in atmtcp_c_send(). syzbot reported the splat below. [0] vcc_sendmsg() copies data passed from userspace to skb and passes it to vcc->dev->ops->send(). atmtcp_c_send() accesses skb->data as struct atmtcp_hdr after checking if skb->len is 0, but it's not enough. Also, when skb->len == 0, skb and sk (vcc) were leaked because dev_kfree_skb() is not called and sk_wmem_alloc adjustment is missing to revert atm_account_tx() in vcc_sendmsg(), which is expected to be done in atm_pop_raw(). Let's properly free skb with an invalid length in atmtcp_c_send(). [0]: BUG: KMSAN: uninit-value in atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294 atmtcp_c_send+0x255/0xed0 drivers/atm/atmtcp.c:294 vcc_sendmsg+0xd7c/0xff0 net/atm/common.c:644 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4154 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4249 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1336 [inline] vcc_sendmsg+0xb40/0xff0 net/atm/common.c:628 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 5798 Comm: syz-executor192 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 | |
| Title | atm: atmtcp: Free invalid length skb in atmtcp_c_send(). | |
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:22:53.484Z
Reserved: 2025-04-16T04:51:23.992Z
Link: CVE-2025-38185
No data.
Status : Analyzed
Published: 2025-07-04T14:15:25.377
Modified: 2025-12-18T16:53:27.463
Link: CVE-2025-38185
OpenCVE Enrichment
Updated: 2025-07-13T21:47:49Z
Debian DLA
Debian DSA
EUVD
Ubuntu USN