In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_fw: fix NULL pointer dereference on shared blocks
The old-method path in fw_classify() calls tcf_block_q() and
dereferences q->handle. Shared blocks leave block->q NULL, causing a
NULL deref when an empty cls_fw filter is attached to a shared block
and a packet with a nonzero major skb mark is classified.
Reject the configuration in fw_change() when the old method (no
TCA_OPTIONS) is used on a shared block, since fw_classify()'s
old-method path needs block->q which is NULL for shared blocks.
The fixed null-ptr-deref calling stack:
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
RIP: 0010:fw_classify (net/sched/cls_fw.c:81)
Call Trace:
tcf_classify (./include/net/tc_wrapper.h:197 net/sched/cls_api.c:1764 net/sched/cls_api.c:1860)
tc_run (net/core/dev.c:4401)
__dev_queue_xmit (net/core/dev.c:4535 net/core/dev.c:4790)
References
Configurations
Configuration 1 (hide)
|
History
20 May 2026, 18:10
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CWE | CWE-476 | |
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
|
| References | () https://git.kernel.org/stable/c/18328eff2f97d1a6adcdb6d4a0f42f2f83a31e28 - Patch | |
| References | () https://git.kernel.org/stable/c/3cb055df9e8625ce699a259d8178d67b37f2b160 - Patch | |
| References | () https://git.kernel.org/stable/c/3d41f9a314afa94b1c7c7c75405920123220e8cd - Patch | |
| References | () https://git.kernel.org/stable/c/5cf41031922c154aa5ccda8bcdb0f5e6226582ec - Patch | |
| References | () https://git.kernel.org/stable/c/96426c348def662b06bfdc65be3002905604927a - Patch | |
| References | () https://git.kernel.org/stable/c/d6d5bd62a09650856e1e2010eb09853eba0d64e1 - Patch | |
| References | () https://git.kernel.org/stable/c/faeea8bbf6e958bf3c00cb08263109661975987c - Patch | |
| References | () https://git.kernel.org/stable/c/febf64ca79a2d6540ab6e5e197fa0f4f7e84473e - Patch | |
| First Time |
Linux linux Kernel
Linux |
18 Apr 2026, 09:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
13 Apr 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-13 14:16
Updated : 2026-05-20 18:10
NVD link : CVE-2026-31421
Mitre link : CVE-2026-31421
CVE.ORG link : CVE-2026-31421
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-476
NULL Pointer Dereference