Description
In the Linux kernel, the following vulnerability has been resolved:
tls: device: fix out-of-bounds write in tls_append_frag()
Found with syzkaller and a local syzbot instance running on top of a
netdevsim TLS offload emulation; tls_device.c is otherwise only reachable
on a machine with a NIC that implements the offload.
tls_push_data() only checks whether the open record still has room for
another frag at the bottom of its loop, and the MSG_MORE early break
skips that check. The record survives to the next syscall with the frag
count it already had, and tls_append_frag() does not check either, so
with TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds
a non-coalescing pipe page and num_frags walks off the end of
tls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed,
tls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and
the sg_set_page() writes land on the destruct_work that follows it, which
the workqueue then calls.
The byte limit is fine because copy drops to 0 and the loop falls through
to the same check; the frag count has no such feedback.
Push the record rather than keep a full one open, which is what a plain
TCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and
new_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw
already sets full_record when the sk_msg ring fills up, MSG_MORE or not.
BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269)
Write of size 8 at addr ffff8881104d1530 by task tls_oob/450
CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
tls_append_frag (net/tls/tls_device.c:269)
tls_push_data (net/tls/tls_device.c:518)
tls_device_sendmsg (net/tls/tls_device.c:583)
inet_sendmsg (net/ipv4/af_inet.c:865)
sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813)
splice_to_socket (fs/splice.c:884)
do_splice (fs/splice.c:936 fs/splice.c:1349)
__do_splice (fs/splice.c:1431)
__x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
</TASK>
and, once the record is pushed:
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24
index 18 is out of range for type 'skb_frag_t [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41
index 18 is out of range for type 'scatterlist [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39
index 18 is out of range for type 'scatterlist [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38
index 26 is out of range for type 'scatterlist [17]'
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle page fault for address: ffffea000411a680
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0011) - permissions violation
Oops: Oops: 0011 [#1] SMP KASAN PTI
Workqueue: ktls_device_destruct 0xffffea000411a680
RIP: 0010:0xffffea000411a680
Call Trace:
<TASK>
worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
</TASK>
tls: device: fix out-of-bounds write in tls_append_frag()
Found with syzkaller and a local syzbot instance running on top of a
netdevsim TLS offload emulation; tls_device.c is otherwise only reachable
on a machine with a NIC that implements the offload.
tls_push_data() only checks whether the open record still has room for
another frag at the bottom of its loop, and the MSG_MORE early break
skips that check. The record survives to the next syscall with the frag
count it already had, and tls_append_frag() does not check either, so
with TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds
a non-coalescing pipe page and num_frags walks off the end of
tls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed,
tls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and
the sg_set_page() writes land on the destruct_work that follows it, which
the workqueue then calls.
The byte limit is fine because copy drops to 0 and the loop falls through
to the same check; the frag count has no such feedback.
Push the record rather than keep a full one open, which is what a plain
TCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and
new_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw
already sets full_record when the sk_msg ring fills up, MSG_MORE or not.
BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269)
Write of size 8 at addr ffff8881104d1530 by task tls_oob/450
CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
tls_append_frag (net/tls/tls_device.c:269)
tls_push_data (net/tls/tls_device.c:518)
tls_device_sendmsg (net/tls/tls_device.c:583)
inet_sendmsg (net/ipv4/af_inet.c:865)
sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813)
splice_to_socket (fs/splice.c:884)
do_splice (fs/splice.c:936 fs/splice.c:1349)
__do_splice (fs/splice.c:1431)
__x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
</TASK>
and, once the record is pushed:
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24
index 18 is out of range for type 'skb_frag_t [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41
index 18 is out of range for type 'scatterlist [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39
index 18 is out of range for type 'scatterlist [17]'
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38
index 26 is out of range for type 'scatterlist [17]'
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle page fault for address: ffffea000411a680
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0011) - permissions violation
Oops: Oops: 0011 [#1] SMP KASAN PTI
Workqueue: ktls_device_destruct 0xffffea000411a680
RIP: 0010:0xffffea000411a680
Call Trace:
<TASK>
worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:158)
ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
</TASK>
Published:
2026-09-04
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
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 | Linux | unaffected |
|
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| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Fri, 04 Sep 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: tls: device: fix out-of-bounds write in tls_append_frag() Found with syzkaller and a local syzbot instance running on top of a netdevsim TLS offload emulation; tls_device.c is otherwise only reachable on a machine with a NIC that implements the offload. tls_push_data() only checks whether the open record still has room for another frag at the bottom of its loop, and the MSG_MORE early break skips that check. The record survives to the next syscall with the frag count it already had, and tls_append_frag() does not check either, so with TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds a non-coalescing pipe page and num_frags walks off the end of tls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed, tls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and the sg_set_page() writes land on the destruct_work that follows it, which the workqueue then calls. The byte limit is fine because copy drops to 0 and the loop falls through to the same check; the frag count has no such feedback. Push the record rather than keep a full one open, which is what a plain TCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and new_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw already sets full_record when the sk_msg ring fills up, MSG_MORE or not. BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269) Write of size 8 at addr ffff8881104d1530 by task tls_oob/450 CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) tls_append_frag (net/tls/tls_device.c:269) tls_push_data (net/tls/tls_device.c:518) tls_device_sendmsg (net/tls/tls_device.c:583) inet_sendmsg (net/ipv4/af_inet.c:865) sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813) splice_to_socket (fs/splice.c:884) do_splice (fs/splice.c:936 fs/splice.c:1349) __do_splice (fs/splice.c:1431) __x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> and, once the record is pushed: UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24 index 18 is out of range for type 'skb_frag_t [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38 index 26 is out of range for type 'scatterlist [17]' kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffea000411a680 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation Oops: Oops: 0011 [#1] SMP KASAN PTI Workqueue: ktls_device_destruct 0xffffea000411a680 RIP: 0010:0xffffea000411a680 Call Trace: <TASK> worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) </TASK> | |
| Title | tls: device: fix out-of-bounds write in tls_append_frag() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-04T15:55:02.806Z
Reserved: 2026-08-26T14:34:25.797Z
Link: CVE-2026-80852
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-04T16:18:14.073
Modified: 2026-09-04T16:18:14.073
Link: CVE-2026-80852
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.