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Linux KernelOperating system · Linux

CVE-2025-38147

MEDIUM · 5.5 CVSS v3.1 Published 2025-07-03
Fix available
A fix is available. Upgrade to 5.4.295 / 5.10.239 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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:

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.8, < 5.4.295>= 5.5, < 5.10.239>= 5.11, < 5.15.186>= 5.16, < 6.1.142>= 6.2, < 6.6.94>= 6.7, < 6.12.34>= 6.13, < 6.15.3
Debian LinuxOperating system
Affected:= 11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.295 / 5.10.239 / 5.15.186 or later
Fixed in 5.4.2955.10.2395.15.186
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel version 5.4.295, 5.10.239, 5.15.186, or 6.1.142 (or later) depending on your current major version branch

  1. 1. Identify the currently running kernel version using `uname -r`
  2. 2. Determine the appropriate kernel version to upgrade to based on your current major version: For kernel 4.8-5.4.x, upgrade to >= 5.4.295; For kernel 5.5-5.10.x, upgrade to >= 5.10.239; For kernel 5.11-5.15.x, upgrade to >= 5.15.186; For kernel 5.16-6.1.x, upgrade to >= 6.1.142; For kernel >= 6.2, the fix is already included
  3. 3. Update the package repository and upgrade the kernel package using the distribution's package manager (e.g., `apt update && apt upgrade` for Debian/Ubuntu, or `yum update` for RHEL/CentOS)
  4. 4. Reboot the system to load the new kernel
  5. 5. Verify the kernel version after reboot using `uname -r` to confirm the fix is applied
Caveat Kernel upgrades may require system restart and could have compatibility implications with third-party kernel modules; ensure backups and test in staging if possible

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-38147 in production — separate from our analysis above.

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