Linux Kernel up to 6.12.39/6.15.7 smc cipso_v4_sock_setattr null pointer dereference

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5.0$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.12.39/6.15.7. The impacted element is the function cipso_v4_sock_setattr of the component smc. The manipulation leads to null pointer dereference. This vulnerability is referenced as CVE-2025-38475. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.39/6.15.7 and classified as critical. This issue affects the function cipso_v4_sock_setattr of the component smc. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: smc: Fix various oops due to inet_sock type confusion. syzbot reported weird splats [0][1] in cipso_v4_sock_setattr() while freeing inet_sk(sk)->inet_opt. The address was freed multiple times even though it was read-only memory. cipso_v4_sock_setattr() did nothing wrong, and the root cause was type confusion. The cited commit made it possible to create smc_sock as an INET socket. The issue is that struct smc_sock does not have struct inet_sock as the first member but hijacks AF_INET and AF_INET6 sk_family, which confuses various places. In this case, inet_sock.inet_opt was actually smc_sock.clcsk_data_ready(), which is an address of a function in the text segment. $ pahole -C inet_sock vmlinux struct inet_sock { ... struct ip_options_rcu * inet_opt; /* 784 8 */ $ pahole -C smc_sock vmlinux struct smc_sock { ... void (*clcsk_data_ready)(struct sock *); /* 784 8 */ The same issue for another field was reported before. [2][3] At that time, an ugly hack was suggested [4], but it makes both INET and SMC code error-prone and hard to change. Also, yet another variant was fixed by a hacky commit 98d4435efcbf3 ("net/smc: prevent NULL pointer dereference in txopt_get"). Instead of papering over the root cause by such hacks, we should not allow non-INET socket to reuse the INET infra. Let's add inet_sock as the first member of smc_sock. [0]: kvfree_call_rcu(): Double-freed call. rcu_head 000000006921da73 WARNING: CPU: 0 PID: 6718 at mm/slab_common.c:1956 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 Modules linked in: CPU: 0 UID: 0 PID: 6718 Comm: syz.0.17 Tainted: G W 6.16.0-rc4-syzkaller-g7482bb149b9f #0 PREEMPT Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 lr : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 sp : ffff8000a03a7730 x29: ffff8000a03a7730 x28: 00000000fffffff5 x27: 1fffe000184823d3 x26: dfff800000000000 x25: ffff0000c2411e9e x24: ffff0000dd88da00 x23: ffff8000891ac9a0 x22: 00000000ffffffea x21: ffff8000891ac9a0 x20: ffff8000891ac9a0 x19: ffff80008afc2480 x18: 00000000ffffffff x17: 0000000000000000 x16: ffff80008ae642c8 x15: ffff700011ede14c x14: 1ffff00011ede14c x13: 0000000000000004 x12: ffffffffffffffff x11: ffff700011ede14c x10: 0000000000ff0100 x9 : 5fa3c1ffaf0ff000 x8 : 5fa3c1ffaf0ff000 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000a03a7078 x4 : ffff80008f766c20 x3 : ffff80008054d360 x2 : 0000000000000000 x1 : 0000000000000201 x0 : 0000000000000000 Call trace: kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 (P) cipso_v4_sock_setattr+0x2f0/0x3f4 net/ipv4/cipso_ipv4.c:1914 netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000 smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581 smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912 security_inode_setsecurity+0x118/0x3c0 security/security.c:2706 __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295 vfs_setxattr+0x158/0x2ac fs/xattr.c:321 do_setxattr fs/xattr.c:636 [inline] file_setxattr+0x1b8/0x294 fs/xattr.c:646 path_setxattrat+0x2ac/0x320 fs/xattr.c:711 __do_sys_fsetxattr fs/xattr.c:761 [inline] __se_sys_fsetxattr fs/xattr.c:758 [inline] __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 [ ---truncated---

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-38475 since 04/16/2025. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 258053 (SUSE SLED15 / SLES15 Security Update : kernel (SUSE-SU-2025:02997-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.40 or 6.15.8 eliminates this vulnerability. Applying the patch 5b02e397929e5b13b969ef1f8e43c7951e2864f5/67a167a6b8b45607bc34aa541d1c75097d18d460/60ada4fe644edaa6c2da97364184b0425e8aeaf5 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (258053) and CERT Bund (WID-SEC-2025-1665). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM QRadar SIEM
  • SUSE openSUSE
  • RESF Rocky Linux
  • Dell Avamar
  • NetApp ActiveIQ Unified Manager
  • Dell PowerProtect Data Domain
  • Open Source Linux Kernel
  • Dell NetWorker
  • Dell Secure Connect Gateway
  • IBM Security Verify Access

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 258053
Nessus Name: SUSE SLED15 / SLES15 Security Update : kernel (SUSE-SU-2025:02997-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.40/6.15.8
Patch: 5b02e397929e5b13b969ef1f8e43c7951e2864f5/67a167a6b8b45607bc34aa541d1c75097d18d460/60ada4fe644edaa6c2da97364184b0425e8aeaf5

Timelineinfo

04/16/2025 CVE reserved
07/28/2025 +103 days Advisory disclosed
07/28/2025 +0 days VulDB entry created
01/25/2026 +181 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38475 (🔒)
GCVE (CVE): GCVE-0-2025-38475
GCVE (VulDB): GCVE-100-317885
CERT Bund: WID-SEC-2025-1665 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 07/28/2025 14:44
Updated: 01/25/2026 13:46
Changes: 07/28/2025 14:44 (59), 08/17/2025 20:23 (7), 08/18/2025 12:24 (1), 08/23/2025 22:14 (1), 08/26/2025 16:03 (1), 08/28/2025 16:14 (2), 10/01/2025 06:01 (1), 10/18/2025 10:01 (1), 11/02/2025 00:36 (1), 11/16/2025 19:16 (1), 11/20/2025 03:31 (12), 01/25/2026 13:46 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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