net/sched: accept TCA_STAB only for root qdisc
Most qdiscs maintain their backlog using qdisc_pkt_len(skb)
on the assumption it is invariant between the enqueue()
and dequeue() handlers.
Unfortunately syzbot can crash a host rather easily using
a TBF + SFQ combination, with an STAB on SFQ [1]
We can't support TCA_STAB on arbitrary level, this would
require to maintain per-qdisc storage.
[1]
[ 88.796496] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 88.798611] #PF: supervisor read access in kernel mode
[ 88.799014] #PF: error_code(0x0000) - not-present page
[ 88.799506] PGD 0 P4D 0
[ 88.799829] Oops: Oops: 0000 [#1] SMP NOPTI
[ 88.800569] CPU: 14 UID: 0 PID: 2053 Comm: b371744477 Not tainted 6.12.0-rc1-virtme #1117
[ 88.801107] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 88.801779] RIP: 0010:sfq_dequeue (net/sched/sch_sfq.c:272 net/sched/sch_sfq.c:499) sch_sfq
[ 88.802544] Code: 0f b7 50 12 48 8d 04 d5 00 00 00 00 48 89 d6 48 29 d0 48 8b 91 c0 01 00 00 48 c1 e0 03 48 01 c2 66 83 7a 1a 00 7e c0 48 8b 3a <4c> 8b 07 4c 89 02 49 89 50 08 48 c7 47 08 00 00 00 00 48 c7 07 00
All code
========
0: 0f b7 50 12 movzwl 0x12(%rax),%edx
4: 48 8d 04 d5 00 00 00 lea 0x0(,%rdx,8),%rax
b: 00
c: 48 89 d6 mov %rdx,%rsi
f: 48 29 d0 sub %rdx,%rax
12: 48 8b 91 c0 01 00 00 mov 0x1c0(%rcx),%rdx
19: 48 c1 e0 03 shl $0x3,%rax
1d: 48 01 c2 add %rax,%rdx
20: 66 83 7a 1a 00 cmpw $0x0,0x1a(%rdx)
25: 7e c0 jle 0xffffffffffffffe7
27: 48 8b 3a mov (%rdx),%rdi
2a:* 4c 8b 07 mov (%rdi),%r8 <-- trapping instruction
2d: 4c 89 02 mov %r8,(%rdx)
30: 49 89 50 08 mov %rdx,0x8(%r8)
34: 48 c7 47 08 00 00 00 movq $0x0,0x8(%rdi)
3b: 00
3c: 48 rex.W
3d: c7 .byte 0xc7
3e: 07 (bad)
...
Code starting with the faulting instruction
===========================================
0: 4c 8b 07 mov (%rdi),%r8
3: 4c 89 02 mov %r8,(%rdx)
6: 49 89 50 08 mov %rdx,0x8(%r8)
a: 48 c7 47 08 00 00 00 movq $0x0,0x8(%rdi)
11: 00
12: 48 rex.W
13: c7 .byte 0xc7
14: 07 (bad)
...
[ 88.803721] RSP: 0018:ffff9a1f892b7d58 EFLAGS: 00000206
[ 88.804032] RAX: 0000000000000000 RBX: ffff9a1f8420c800 RCX: ffff9a1f8420c800
[ 88.804560] RDX: ffff9a1f81bc1440 RSI: 0000000000000000 RDI: 0000000000000000
[ 88.805056] RBP: ffffffffc04bb0e0 R08: 0000000000000001 R09: 00000000ff7f9a1f
[ 88.805473] R10: 000000000001001b R11: 0000000000009a1f R12: 0000000000000140
[ 88.806194] R13: 0000000000000001 R14: ffff9a1f886df400 R15: ffff9a1f886df4ac
[ 88.806734] FS: 00007f445601a740(0000) GS:ffff9a2e7fd80000(0000) knlGS:0000000000000000
[ 88.807225] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 88.807672] CR2: 0000000000000000 CR3: 000000050cc46000 CR4: 00000000000006f0
[ 88.808165] Call Trace:
[ 88.808459] <TASK>
[ 88.808710] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434)
[ 88.809261] ? page_fault_oops (arch/x86/mm/fault.c:715)
[ 88.809561] ? exc_page_fault (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:87 ./arch/x86/include/asm/irqflags.h:147 arch/x86/mm/fault.c:1489 arch/x86/mm/fault.c:1539)
[ 88.809806] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623)
[ 88.810074] ? sfq_dequeue (net/sched/sch_sfq.c:272 net/sched/sch_sfq.c:499) sch_sfq
[ 88.810411] sfq_reset (net/sched/sch_sfq.c:525) sch_sfq
[ 88.810671] qdisc_reset (./include/linux/skbuff.h:2135 ./include/linux/skbuff.h:2441 ./include/linux/skbuff.h:3304 ./include/linux/skbuff.h:3310 net/sched/sch_g
---truncated---
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4008-1 | linux-6.1 security update |
Debian DLA |
DLA-4075-1 | linux security update |
Ubuntu USN |
USN-7166-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7166-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7166-3 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7166-4 | Linux kernel (Xilinx ZynqMP) vulnerabilities |
Ubuntu USN |
USN-7186-1 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-7186-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7194-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7276-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7277-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7293-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7294-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7294-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7294-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7294-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7295-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7310-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7383-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7383-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7384-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7384-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7385-1 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-7386-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7393-1 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7401-1 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7403-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7413-1 | Linux kernel (IoT) vulnerabilities |
Ubuntu USN |
USN-7451-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7468-1 | Linux kernel (Azure, N-Series) vulnerabilities |
Ubuntu USN |
USN-7523-1 | Linux kernel (Raspberry Pi Real-time) vulnerabilities |
Ubuntu USN |
USN-7524-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7539-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7540-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Tue, 12 May 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Mon, 03 Nov 2025 23:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Mon, 03 Nov 2025 21:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Wed, 16 Jul 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
epss
|
epss
|
Wed, 14 May 2025 02:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat
Redhat enterprise Linux |
|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
|
| Vendors & Products |
Redhat
Redhat enterprise Linux |
Fri, 08 Nov 2024 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Fri, 25 Oct 2024 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Weaknesses | CWE-476 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Tue, 22 Oct 2024 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 22 Oct 2024 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Mon, 21 Oct 2024 19:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/sched: accept TCA_STAB only for root qdisc Most qdiscs maintain their backlog using qdisc_pkt_len(skb) on the assumption it is invariant between the enqueue() and dequeue() handlers. Unfortunately syzbot can crash a host rather easily using a TBF + SFQ combination, with an STAB on SFQ [1] We can't support TCA_STAB on arbitrary level, this would require to maintain per-qdisc storage. [1] [ 88.796496] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 88.798611] #PF: supervisor read access in kernel mode [ 88.799014] #PF: error_code(0x0000) - not-present page [ 88.799506] PGD 0 P4D 0 [ 88.799829] Oops: Oops: 0000 [#1] SMP NOPTI [ 88.800569] CPU: 14 UID: 0 PID: 2053 Comm: b371744477 Not tainted 6.12.0-rc1-virtme #1117 [ 88.801107] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 88.801779] RIP: 0010:sfq_dequeue (net/sched/sch_sfq.c:272 net/sched/sch_sfq.c:499) sch_sfq [ 88.802544] Code: 0f b7 50 12 48 8d 04 d5 00 00 00 00 48 89 d6 48 29 d0 48 8b 91 c0 01 00 00 48 c1 e0 03 48 01 c2 66 83 7a 1a 00 7e c0 48 8b 3a <4c> 8b 07 4c 89 02 49 89 50 08 48 c7 47 08 00 00 00 00 48 c7 07 00 All code ======== 0: 0f b7 50 12 movzwl 0x12(%rax),%edx 4: 48 8d 04 d5 00 00 00 lea 0x0(,%rdx,8),%rax b: 00 c: 48 89 d6 mov %rdx,%rsi f: 48 29 d0 sub %rdx,%rax 12: 48 8b 91 c0 01 00 00 mov 0x1c0(%rcx),%rdx 19: 48 c1 e0 03 shl $0x3,%rax 1d: 48 01 c2 add %rax,%rdx 20: 66 83 7a 1a 00 cmpw $0x0,0x1a(%rdx) 25: 7e c0 jle 0xffffffffffffffe7 27: 48 8b 3a mov (%rdx),%rdi 2a:* 4c 8b 07 mov (%rdi),%r8 <-- trapping instruction 2d: 4c 89 02 mov %r8,(%rdx) 30: 49 89 50 08 mov %rdx,0x8(%r8) 34: 48 c7 47 08 00 00 00 movq $0x0,0x8(%rdi) 3b: 00 3c: 48 rex.W 3d: c7 .byte 0xc7 3e: 07 (bad) ... Code starting with the faulting instruction =========================================== 0: 4c 8b 07 mov (%rdi),%r8 3: 4c 89 02 mov %r8,(%rdx) 6: 49 89 50 08 mov %rdx,0x8(%r8) a: 48 c7 47 08 00 00 00 movq $0x0,0x8(%rdi) 11: 00 12: 48 rex.W 13: c7 .byte 0xc7 14: 07 (bad) ... [ 88.803721] RSP: 0018:ffff9a1f892b7d58 EFLAGS: 00000206 [ 88.804032] RAX: 0000000000000000 RBX: ffff9a1f8420c800 RCX: ffff9a1f8420c800 [ 88.804560] RDX: ffff9a1f81bc1440 RSI: 0000000000000000 RDI: 0000000000000000 [ 88.805056] RBP: ffffffffc04bb0e0 R08: 0000000000000001 R09: 00000000ff7f9a1f [ 88.805473] R10: 000000000001001b R11: 0000000000009a1f R12: 0000000000000140 [ 88.806194] R13: 0000000000000001 R14: ffff9a1f886df400 R15: ffff9a1f886df4ac [ 88.806734] FS: 00007f445601a740(0000) GS:ffff9a2e7fd80000(0000) knlGS:0000000000000000 [ 88.807225] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 88.807672] CR2: 0000000000000000 CR3: 000000050cc46000 CR4: 00000000000006f0 [ 88.808165] Call Trace: [ 88.808459] <TASK> [ 88.808710] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434) [ 88.809261] ? page_fault_oops (arch/x86/mm/fault.c:715) [ 88.809561] ? exc_page_fault (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:87 ./arch/x86/include/asm/irqflags.h:147 arch/x86/mm/fault.c:1489 arch/x86/mm/fault.c:1539) [ 88.809806] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623) [ 88.810074] ? sfq_dequeue (net/sched/sch_sfq.c:272 net/sched/sch_sfq.c:499) sch_sfq [ 88.810411] sfq_reset (net/sched/sch_sfq.c:525) sch_sfq [ 88.810671] qdisc_reset (./include/linux/skbuff.h:2135 ./include/linux/skbuff.h:2441 ./include/linux/skbuff.h:3304 ./include/linux/skbuff.h:3310 net/sched/sch_g ---truncated--- | |
| Title | net/sched: accept TCA_STAB only for root qdisc | |
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-12T11:59:51.952Z
Reserved: 2024-10-21T12:17:06.070Z
Link: CVE-2024-50039
Updated: 2025-11-03T22:24:45.361Z
Status : Modified
Published: 2024-10-21T20:15:16.957
Modified: 2026-05-12T13:16:16.120
Link: CVE-2024-50039
OpenCVE Enrichment
No data.
Debian DLA
Ubuntu USN