Cloudanix VulnDB

CVE-2025-38147

None

CVSS

—

EPSS

0.2%

Published

Jul 3, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in the Linux kernel's handling of network security labels can let specially crafted connection attempts crash the entire system.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Improper Input Validation
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Missing address family validation in netlbl_conn_setattr() allows IPv6 calipso paths to be invoked on AF_INET sockets, resulting in null dereference of ipv6_pinfo within txopt_get().

Why it matters to the business

Kernel crashes or denial of service on Linux systems using SELinux network labeling, potentially disrupting servers and containers until patched; prevalence in downstream Linux distributions increases exposure surface.

How an attack unfolds

An attacker creates an IPv4 socket and issues a connect() call supplying an IPv6 sockaddr; the call reaches security_socket_connect and netlbl_conn_setattr() before family validation occurs, causing the kernel to dereference a NULL ipv6_pinfo pointer.

How to fix it

Upgrade to fixed kernel versions containing commit fc2da88411470480b8b7e9177e930cedd893cf56 or Chainguard nsc-fips 2.11.0-r2; apply the added address-family validation in netlbl_conn_setattr().

How to confirm the fix worked

Confirm presence of the family check in netlbl_conn_setattr(), verify kernel build contains the referenced commit, and test that IPv6 connect attempts on IPv4 sockets no longer trigger the oops.

Typical attack path

  1. Create AF_INET socket via socket()
  2. Invoke connect() supplying AF_INET6 sockaddr from userspace
  3. Trigger selinux_socket_connect and selinux_netlbl_socket_connect paths
  4. Enter netlbl_conn_setattr() which dispatches on sockaddr family without socket match check
  5. Call calipso_sock_setattr() leading to txopt_get() NULL dereference

How to detect it

Search kernel logs and crash dumps for stack traces containing txopt_get, calipso_sock_setattr, netlbl_conn_setattr, and selinux_netlbl_socket_connect; correlate with connect syscalls from untrusted processes.

  • txopt_get include/net/ipv6.h:390
  • calipso_sock_setattr+0x56/0x80 net/netlabel/netlabel_calipso.c:557
  • KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
  • netlbl_conn_setattr+0x10c/0x280 net/netlabel/netlabel_kapi.c:1177

What your security team should do

  • Apply the referenced kernel fixes immediately on all affected distributions
  • Restrict untrusted code from creating sockets and performing cross-family connect operations
  • Monitor kernel logs for oops involving txopt_get and calipso_sock_setattr

The record

In the Linux kernel, the following vulnerability has been resolved: calipso: Don't call calipso functions for AF_INET sk. syzkaller reported a null-ptr-deref in txopt_get(). [0] The offset 0x70 was of struct ipv6_txoptions in struct ipv6_pinfo, so struct ipv6_pinfo was NULL there. However, this never happens for IPv6 sockets as inet_sk(sk)->pinet6 is always set in inet6_create(), meaning the socket was not IPv6 one. The root cause is missing validation in netlbl_conn_setattr(). netlbl_conn_setattr() switches branches based on struct sockaddr.sa_family, which is passed from userspace. However, netlbl_conn_setattr() does not check if the address family matches the socket. The syzkaller must have called connect() for an IPv6 address on an IPv4 socket. We have a proper validation in tcp_v[46]_connect(), but security_socket_connect() is called in the earlier stage. Let's copy the validation to netlbl_conn_setattr(). [0]: Oops: general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077] CPU: 2 UID: 0 PID: 12928 Comm: syz.9.1677 Not tainted 6.12.0 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:txopt_get include/net/ipv6.h:390 [inline] RIP: 0010: Code: 02 00 00 49 8b ac 24 f8 02 00 00 e8 84 69 2a fd e8 ff 00 16 fd 48 8d 7d 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 53 02 00 00 48 8b 6d 70 48 85 ed 0f 84 ab 01 00 RSP: 0018:ffff88811b8afc48 EFLAGS: 00010212 RAX: dffffc0000000000 RBX: 1ffff11023715f8a RCX: ffffffff841ab00c RDX: 000000000000000e RSI: ffffc90007d9e000 RDI: 0000000000000070 RBP: 0000000000000000 R08: ffffed1023715f9d R09: ffffed1023715f9e R10: ffffed1023715f9d R11: 0000000000000003 R12: ffff888123075f00 R13: ffff88810245bd80 R14: ffff888113646780 R15: ffff888100578a80 FS: 00007f9019bd7640(0000) GS:ffff8882d2d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f901b927bac CR3: 0000000104788003 CR4: 0000000000770ef0 PKRU: 80000000 Call Trace: <TASK> calipso_sock_setattr+0x56/0x80 net/netlabel/netlabel_calipso.c:557 netlbl_conn_setattr+0x10c/0x280 net/netlabel/netlabel_kapi.c:1177 selinux_netlbl_socket_connect_helper+0xd3/0x1b0 security/selinux/netlabel.c:569 selinux_netlbl_socket_connect_locked security/selinux/netlabel.c:597 [inline] selinux_netlbl_socket_connect+0xb6/0x100 security/selinux/netlabel.c:615 selinux_socket_connect+0x5f/0x80 security/selinux/hooks.c:4931 security_socket_connect+0x50/0xa0 security/security.c:4598 __sys_connect_file+0xa4/0x190 net/socket.c:2067 __sys_connect+0x12c/0x170 net/socket.c:2088 __do_sys_connect net/socket.c:2098 [inline] __se_sys_connect net/socket.c:2095 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:2095 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xaa/0x1b0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f901b61a12d Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9019bd6fa8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f901b925fa0 RCX: 00007f901b61a12d RDX: 000000000000001c RSI: 0000200000000140 RDI: 0000000000000003 RBP: 00007f901b701505 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f901b5b62a0 R15: 00007f9019bb7000 </TASK> Modules linked in:

Affected packages

Ecosystem Package Introduced Fixed
Debian:11 linux 0 No fix
Debian:12 linux 0 No fix
Debian:13 linux 0 No fix
Debian:14 linux 0 6.12.35-1
Linux Kernel 4.8.0 5.4.295
Mageia:9 kernel 0 6.6.101-1.mga9
Mageia:9 kernel-linus 0 6.6.101-1.mga9
Mageia:9 kmod-virtualbox 0 7.1.10-7.mga9
Mageia:9 kmod-xtables-addons 0 3.24-83.mga9
Mageia:9 wireless-regdb 0 20250710-1.mga9
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Live Patching 12 SP5 kernel-default 0 4.12.14-122.269.1
SUSE:Linux Enterprise Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_71 0 1-8.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_14 0 1-150600.1.5.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_14 0 1-150600.13.3.4
SUSE:Linux Enterprise Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_3 0 1-150700.1.5.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-64kb 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default-base 0 6.4.0-150600.23.65.1.150600.12.28.4
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-source 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-zfcpdump 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco 0 6.4.0-15061.28.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco_debug 0 6.4.0-15061.28.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-source-coco 0 6.4.0-15061.28.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-syms-coco 0 6.4.0-15061.28.coco15sp6.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-docs 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-obs-build 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-source 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-syms 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Legacy 15 SP6 kernel-default 0 6.4.0-150600.23.65.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-azure 0 6.4.0-150600.8.48.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure 0 6.4.0-150600.8.48.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-syms-azure 0 6.4.0-150600.8.48.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-default 0 4.12.14-122.269.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-source 0 4.12.14-122.269.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-syms 0 4.12.14-122.269.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-default 0 4.12.14-122.269.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source 0 4.12.14-122.269.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-syms 0 4.12.14-122.269.1
SUSE:Linux Enterprise Workstation Extension 15 SP6 kernel-default 0 6.4.0-150600.23.65.1
SUSE:Real Time Module 15 SP6 kernel-rt 0 6.4.0-150600.10.49.1
SUSE:Real Time Module 15 SP6 kernel-rt_debug 0 6.4.0-150600.10.49.1
SUSE:Real Time Module 15 SP6 kernel-source-rt 0 6.4.0-150600.10.49.1
SUSE:Real Time Module 15 SP6 kernel-syms-rt 0 6.4.0-150600.10.49.1
SUSE:Real Time Module 15 SP7 kernel-rt 0 6.4.0-150700.7.13.1
SUSE:Real Time Module 15 SP7 kernel-source-rt 0 6.4.0-150700.7.13.1
SUSE:Real Time Module 15 SP7 kernel-syms-rt 0 6.4.0-150700.7.13.1
openSUSE:Leap 15.6 dtb-aarch64 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-64kb 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-azure 0 6.4.0-150600.8.48.1
openSUSE:Leap 15.6 kernel-debug 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-default 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-default-base 0 6.4.0-150600.23.65.1.150600.12.28.4
openSUSE:Leap 15.6 kernel-docs 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-kvmsmall 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-obs-build 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-obs-qa 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-rt 0 6.4.0-150600.10.49.1
openSUSE:Leap 15.6 kernel-rt_debug 0 6.4.0-150600.10.49.1
openSUSE:Leap 15.6 kernel-source 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-source-azure 0 6.4.0-150600.8.48.1
openSUSE:Leap 15.6 kernel-source-rt 0 6.4.0-150600.10.49.1
openSUSE:Leap 15.6 kernel-syms 0 6.4.0-150600.23.65.1
openSUSE:Leap 15.6 kernel-syms-azure 0 6.4.0-150600.8.48.1
openSUSE:Leap 15.6 kernel-syms-rt 0 6.4.0-150600.10.49.1
openSUSE:Leap 15.6 kernel-zfcpdump 0 6.4.0-150600.23.65.1

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