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

bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check

start and len are u32, so

u64 last = start + len;

evaluates start + len in 32-bit and wraps before storing it in last.
The bounds check

if (start >= offset + l || last > msg->sg.size)
return -EINVAL;

can then be passed with an out-of-range start/len, after which the pop
loop runs off the end of the scatterlist and sk_msg_shift_left() calls
put_page() on the empty msg->sg.end slot:

Oops: general protection fault, probably for non-canonical address
0xdffffc0000000001: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline]
RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline]
RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984
Call Trace:
<TASK>
bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8
bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746
sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934
tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline]
tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583
__sock_sendmsg+0x153/0x1c0 net/socket.c:802
__sys_sendto+0x326/0x430 net/socket.c:2265
__x64_sys_sendto+0xe3/0x100 net/socket.c:2268
do_syscall_64+0x14c/0x480
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>

Widen the addition with a (u64) cast so the bound is evaluated in
64-bit and a len near U32_MAX no longer wraps below msg->sg.size.

While here, change pop from int to u32. It counts bytes against the
unsigned scatterlist lengths and can never be negative, so the signed
type only invites sign-confusion in the pop loop.
Published: 2026-08-15
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Sat, 15 Aug 2026 06:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check start and len are u32, so u64 last = start + len; evaluates start + len in 32-bit and wraps before storing it in last. The bounds check if (start >= offset + l || last > msg->sg.size) return -EINVAL; can then be passed with an out-of-range start/len, after which the pop loop runs off the end of the scatterlist and sk_msg_shift_left() calls put_page() on the empty msg->sg.end slot: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline] RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline] RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984 Call Trace: <TASK> bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8 bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746 sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934 tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline] tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583 __sock_sendmsg+0x153/0x1c0 net/socket.c:802 __sys_sendto+0x326/0x430 net/socket.c:2265 __x64_sys_sendto+0xe3/0x100 net/socket.c:2268 do_syscall_64+0x14c/0x480 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Widen the addition with a (u64) cast so the bound is evaluated in 64-bit and a len near U32_MAX no longer wraps below msg->sg.size. While here, change pop from int to u32. It counts bytes against the unsigned scatterlist lengths and can never be negative, so the signed type only invites sign-confusion in the pop loop.
Title bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-15T05:57:34.956Z

Reserved: 2026-08-15T05:44:03.876Z

Link: CVE-2026-74256

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:22:24.743

Modified: 2026-08-15T06:22:24.743

Link: CVE-2026-74256

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

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