CVE-2026-98095

af_packet: Don't cast tpacket_hdr.tp_len to int in tpacket_parse_header().

Published Sep 25, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed

Description

In the Linux kernel, the following vulnerability has been resolved:

af_packet: Don't cast tpacket_hdr.tp_len to int in tpacket_parse_header().

syzbot reported BUG() in sock_sendmsg_nosec(). [0]

The problem is that tpacket_parse_header() casts user-provided
tpacket_hdr.tp_len, which is u32, to int.

If the length is larger than INT_MAX, the following condition
in tpacket_parse_header() passes,

if (unlikely(tp_len > size_max))

and any negative value can be returned to the caller, up to
sock_sendmsg_nosec().

The repro set tpacket_hdr.tp_len to 0xfffffdef, which is cast
to -EIOCBQUEUED (-529), triggering BUG() in sock_sendmsg_nosec().

*(uint64_t*)0x200000000008 = 0xfffffdef;
...
syscall(__NR_write, /*fd=*/r[0], /*buf=*/0x200000000000ul, /*count=*/1ul);

Let's define the local tp_len as u32 in tpacket_parse_header().

[0]:
kernel BUG at net/socket.c:803!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5628 Comm: syz-executor176 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:sock_sendmsg_nosec+0x145/0x180 net/socket.c:803
Code: 06 67 48 0f b9 3a eb 95 e8 e8 3a 22 f8 48 89 df 4c 89 f6 4c 89 e2 4d 89 fb 2e e8 32 a5 5c 16 e9 51 ff ff ff e8 cc 3a 22 f8 90 <0f> 0b e8 c4 3a 22 f8 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28
RSP: 0018:ffffc90003aefb48 EFLAGS: 00010293
RAX: ffffffff89a578d4 RBX: ffff8880764c67c0 RCX: ffff88807fb23e80
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: 00000000fffffdef R08: ffffc90003aef747 R09: 1ffff9200075dee8
R10: dffffc0000000000 R11: fffff5200075dee9 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffc90003aefbc0 R15: ffffffff8aac4310
FS: 000055559101b400(0000) GS:ffff888124ce0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000210 CR3: 0000000073dca000 CR4: 00000000003526f0
Call Trace:
<TASK>
__sock_sendmsg net/socket.c:815 [inline]
sock_write_iter+0x2de/0x3e0 net/socket.c:1266
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f173130ecb9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd67e44248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f173130ecb9
RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd67e44388
R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002
</TASK>

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 3e0cad1432a0c0564f5076bab16f1aa4c0474be4
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 6d4d55f75fa0ea32d874eb33e356e9361f3e4591
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 09e3c9b32434600a6992e762bf0d6837f5902134
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 2b9fa12fbdbfc0f671ff23b0ea06c177a6b8a6b8
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< c6b3db727876a027013aa4ccb6913a153a2af41a
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 72abe77e88c3f1f71c5348124e9b28e285f26950
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 9d714076ff398ba8cc5ae0ae146f4a1ea0bbf5e8
`69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1`	affected	< 73e594c19b4f815d8343461cec7074c4713bbde7

Linux

affected

Version	Status	Constraints
`2.6.31`	affected	—
`0`	unaffected	< 2.6.31
`5.10.271`	unaffected	≤ 5.10.*
`5.15.222`	unaffected	≤ 5.15.*
`6.1.189`	unaffected	≤ 6.1.*
`6.6.158`	unaffected	≤ 6.6.*
`6.12.111`	unaffected	≤ 6.12.*
`6.18.53`	unaffected	≤ 6.18.*
`7.2.7`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:7.3:rc1::::::

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1,c6b3db727876a027013aa4ccb6913a153a2af41a)`	affected	code_commit	—
`[69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1,72abe77e88c3f1f71c5348124e9b28e285f26950)`	affected	code_commit	—
`[69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1,9d714076ff398ba8cc5ae0ae146f4a1ea0bbf5e8)`	affected	code_commit	—
`[69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1,73e594c19b4f815d8343461cec7074c4713bbde7)`	affected	code_commit	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`2.6.31`	affected	semver	—
`[0,2.6.31)`	unaffected	semver	—
`[6.12.111,6.13.0)`	unaffected	semver	—
`[6.18.53,6.19.0)`	unaffected	semver	—
`[7.2.7,7.3.0)`	unaffected	semver	—
`[7.3-rc2,*]`	unaffected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4817-1	linux-6.12 security update
Debian DLA	DLA-4841-1	linux security update
Debian DSA	DSA-6528-1	linux security update
Ubuntu USN	USN-8961-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9022-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9023-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9024-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9025-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9026-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9029-1	Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN	USN-9039-1	Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN	USN-9040-1	Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN	USN-9066-1	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-9091-1	Linux kernel (NVIDIA Tegra) vulnerabilities

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.123% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/09e3c9b32434600a6992e762bf0d6837f5902134
https://git.kernel.org/stable/c/2b9fa12fbdbfc0f671ff23b0ea06c177a6b8a6b8
https://git.kernel.org/stable/c/3e0cad1432a0c0564f5076bab16f1aa4c0474be4
https://git.kernel.org/stable/c/6d4d55f75fa0ea32d874eb33e356e9361f3e4591
https://git.kernel.org/stable/c/72abe77e88c3f1f71c5348124e9b28e285f26950
https://git.kernel.org/stable/c/73e594c19b4f815d8343461cec7074c4713bbde7
https://git.kernel.org/stable/c/9d714076ff398ba8cc5ae0ae146f4a1ea0bbf5e8
https://git.kernel.org/stable/c/c6b3db727876a027013aa4ccb6913a153a2af41a

History

Oct 23, 2026 8:30 PM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses	CWE-190

Oct 23, 2026 6:30 PM Weaknesses updated. Affected versions updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-681
CPEs		cpe:2.3:o:linux:linux_kernel:7.3:rc1::::::
Metrics		cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}`

Oct 3, 2026 11:15 AM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/09e3c9b32434600a6992e762bf0d6837f5902134 https://git.kernel.org/stable/c/2b9fa12fbdbfc0f671ff23b0ea06c177a6b8a6b8 https://git.kernel.org/stable/c/3e0cad1432a0c0564f5076bab16f1aa4c0474be4 https://git.kernel.org/stable/c/6d4d55f75fa0ea32d874eb33e356e9361f3e4591

Sep 25, 2026 4:30 PM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-190

Sep 25, 2026 10:30 AM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: af_packet: Don't cast tpacket_hdr.tp_len to int in tpacket_parse_header(). syzbot reported BUG() in sock_sendmsg_nosec(). [0] The problem is that tpacket_parse_header() casts user-provided tpacket_hdr.tp_len, which is u32, to int. If the length is larger than INT_MAX, the following condition in tpacket_parse_header() passes, if (unlikely(tp_len > size_max)) and any negative value can be returned to the caller, up to sock_sendmsg_nosec(). The repro set tpacket_hdr.tp_len to 0xfffffdef, which is cast to -EIOCBQUEUED (-529), triggering BUG() in sock_sendmsg_nosec(). (uint64_t)0x200000000008 = 0xfffffdef; ... syscall(__NR_write, /fd=/r[0], /buf=/0x200000000000ul, /count=/1ul); Let's define the local tp_len as u32 in tpacket_parse_header(). [0]: kernel BUG at net/socket.c:803! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 5628 Comm: syz-executor176 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:sock_sendmsg_nosec+0x145/0x180 net/socket.c:803 Code: 06 67 48 0f b9 3a eb 95 e8 e8 3a 22 f8 48 89 df 4c 89 f6 4c 89 e2 4d 89 fb 2e e8 32 a5 5c 16 e9 51 ff ff ff e8 cc 3a 22 f8 90 <0f> 0b e8 c4 3a 22 f8 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28 RSP: 0018:ffffc90003aefb48 EFLAGS: 00010293 RAX: ffffffff89a578d4 RBX: ffff8880764c67c0 RCX: ffff88807fb23e80 RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef RBP: 00000000fffffdef R08: ffffc90003aef747 R09: 1ffff9200075dee8 R10: dffffc0000000000 R11: fffff5200075dee9 R12: 0000000000000001 R13: dffffc0000000000 R14: ffffc90003aefbc0 R15: ffffffff8aac4310 FS: 000055559101b400(0000) GS:ffff888124ce0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000210 CR3: 0000000073dca000 CR4: 00000000003526f0 Call Trace: <TASK> __sock_sendmsg net/socket.c:815 [inline] sock_write_iter+0x2de/0x3e0 net/socket.c:1266 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f173130ecb9 Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd67e44248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f173130ecb9 RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd67e44388 R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002 </TASK>
Title		af_packet: Don't cast tpacket_hdr.tp_len to int in tpacket_parse_header().
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/72abe77e88c3f1f71c5348124e9b28e285f26950 https://git.kernel.org/stable/c/73e594c19b4f815d8343461cec7074c4713bbde7 https://git.kernel.org/stable/c/9d714076ff398ba8cc5ae0ae146f4a1ea0bbf5e8 https://git.kernel.org/stable/c/c6b3db727876a027013aa4ccb6913a153a2af41a