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.

Project Subscriptions

Vendors Products
Linux Kernel Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sat, 15 Aug 2026 18:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-190
CWE-20

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

Projects

Sign in to view the affected projects.

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

Updated: 2026-08-15T18:30:12Z

Weaknesses