CVE-2026-98302— net: fddi: skfp: fix NULL deref when setting the MAC address while down
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Linux 内核中，已修复以下漏洞： 网络子系统：fddi: skfp：在接口关闭状态下设置 MAC 地址时修复空指针解引用问题 无条件调用 ，而未检查 。 首先调用 ，将 设置为 ；随后调用 ，该函数遍历两个发送队列： 仅由 填充，而 通过 -> -> -> -> -> 这条路径被调用。私有区域由 分配并初始化为零。因此，对于从未被激活（bring up）的接口，两个队列指针仍然为 。 顶部的 测试未能捕获此问题，因为 刚刚设置了 状态；函数随后进入循环并尝试解引用 指针。虽然 自身也会调用 ，但这是在清空队
Possible ATT&CK Techniques 1 AI
T1203 · Exploitation for Client ExecutionAffected Version Matrix 18
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 835903bea770ad96ab4322e18d98e00f8e0b39c3 |
affected |
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 5fd0f401b3eee95c93daa35ef99cb03d676031f0 |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 731db6110b3148331ed8d5d11a564bfd520721d9 |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 822903ed991971780db1db1be31a4f00e2b13e30 |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 616ba18b2cfb72b7bea214bdd72df2485b2e37dc |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< d6f63fdb298d546a47790cb373db65462c264d04 |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 438131e7ae847e907d345bf504d7e25585561b5c |
affected | ||
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 7c8810c2e69c3d9ca6df870b40ae9218e50b4fb1 |
affected | ||
| … +10 more rows | |||
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I. Basic Information for CVE-2026-98302
Vulnerability Information
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Vulnerability Title
net: fddi: skfp: fix NULL deref when setting the MAC address while down
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
net: fddi: skfp: fix NULL deref when setting the MAC address while down
skfp_ctl_set_mac_address() calls ResetAdapter() unconditionally, without
checking netif_running(). ResetAdapter() first calls card_stop(), which
sets smc->hw.hw_state to STOPPED, and then mac_drv_clear_tx_queue(),
which walks the two transmit queues:
for (i = QUEUE_S; i <= QUEUE_A0; i++) {
queue = smc->hw.fp.tx[i] ;
...
t = queue->tx_curr_get ;
smc->hw.fp.tx[] is only populated by init_tx(), which is reached from
skfp_open() through init_smt() -> init_fddi_driver() -> init_fplus() ->
init_mac() -> init_tx(). The private area is allocated and zeroed by
alloc_fddidev(), so on an interface that has never been brought up both
queue pointers are still NULL. The hw_state test at the top of
mac_drv_clear_tx_queue() does not catch this, because card_stop() has
just set STOPPED; the function proceeds into the loop and dereferences
NULL. ResetAdapter() does call init_smt() itself, but only after the
queues have been cleared.
Setting the MAC address on a down interface therefore oopses:
ip link set dev fddi0 address 02:00:00:00:00:01
BUG: KASAN: null-ptr-deref in mac_drv_clear_tx_queue+0x68/0x2c0 [skfp]
Read of size 8 at addr 0000000000000010 by task ip/302
Call Trace:
<TASK>
mac_drv_clear_tx_queue+0x68/0x2c0 [skfp 6c01d4bab63c36978bd0a7d7e90837adb44cc37b]
ResetAdapter+0x29/0x100 [skfp 6c01d4bab63c36978bd0a7d7e90837adb44cc37b]
skfp_ctl_set_mac_address+0x57/0x80 [skfp 6c01d4bab63c36978bd0a7d7e90837adb44cc37b]
netif_set_mac_address+0x1e4/0x2c0
do_setlink+0x684/0x2680
</TASK>
Address 0x10 is the offset of tx_curr_get, the third pointer in
struct s_smt_tx_queue, on 64-bit. mac_drv_clear_rx_queue(), which
ResetAdapter() calls immediately afterwards, dereferences
smc->hw.fp.rx[QUEUE_R1] in the same way behind the same ineffective
hw_state test; the transmit queue merely crashes first. Both are
covered by the guard below.
Skip the adapter reset when the interface is down. dev_addr_set() is
left unconditional, so the new address is still recorded in
dev->dev_addr. Nothing is lost by not resetting the adapter here:
skfp_open() deliberately re-reads the factory address on every open,
read_address(smc, NULL);
eth_hw_addr_set(dev, smc->hw.fddi_canon_addr.a);
and the comment above it states this is done to discard exactly such an
address override across a close/open cycle. An address set while the
interface is down could not have survived the following open even
before this change, so the guard removes no working behaviour. Guarding
the hardware side of ndo_set_mac_address() with netif_running() is
established practice; skge_set_mac_address() has done so since commit
2eb3e621c4e0 ("skge: set mac address bonding fix").
Guarding the reset as a whole, rather than NULL-checking the queues, is
also what the rest of the driver expects. After a previous open/close
the queue pointers are stale but non-NULL, so there is no crash, yet
ResetAdapter() goes on to call smt_online() and STI_FBI() ("Enable
Board Interrupts") while skfp_close() has already called free_irq() -
the adapter would be brought back online with no handler installed. The
only other ResetAdapter() caller is skfp_interrupt(), which by
construction runs only while the device is open.
Found by automated driver testing against an emulated SysKonnect FDDI
adapter under a KASAN-enabled 7.0.0 kernel. Triggering it requires
CAP_NET_ADMIN.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-98302
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-98302 (8)
Same Patch Batch · Linux · 2026-10-06 · 208 CVEs total
| CVE-2026-98323 | 9.8 CRITICAL | RDMA/siw: Bound fragmented header copies by the remaining length |
| CVE-2026-98365 | 9.8 CRITICAL | RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access |
| CVE-2026-98282 | 8.8 HIGH | powerpc/iommu: Fix the overflow validation in iommu_tce_check_ioba |
| CVE-2026-98283 | 8.8 HIGH | KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid() |
| CVE-2026-98339 | 8.8 HIGH | wifi: cfg80211: don't filter by BSS type when removing stale entries |
| CVE-2026-98171 | 8.8 HIGH | smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs |
| CVE-2026-98261 | 8.1 HIGH | cifs: Fix server use-after-free in cifs_chan_skip_or_disable() |
| CVE-2026-98357 | 8.1 HIGH | IB/isert: wait for deferred control PDU completions before releasing the connection |
| CVE-2026-98239 | 8.1 HIGH | net: lan743x: fix RX checksum use-after-free |
| CVE-2026-98305 | 7.8 HIGH | net: dsa: mxl862xx: disable the stats poll on teardown |
| CVE-2026-98341 | 7.8 HIGH | wifi: cfg80211: don't free driver-owned scan requests |
| CVE-2026-98320 | 7.8 HIGH | netfilter: flowtable: hold reference on ct until flow is released |
| CVE-2026-98228 | 7.8 HIGH | mips: select CONFIG_WEAK_REORDERING_BEYOND_LLSC from CONFIG_EYEQ |
| CVE-2026-98229 | 7.8 HIGH | xfrm: save input state data before secpath resets |
| CVE-2026-98318 | 7.8 HIGH | smb: client: validate absolute native symlink targets before NT fixups |
| CVE-2026-98315 | 7.8 HIGH | ntfs: protect runlist updates with the runlist lock |
| CVE-2026-98260 | 7.8 HIGH | exec: Cleanup POSIX timers right after de_thread() |
| CVE-2026-98256 | 7.8 HIGH | signal: Prevent exec() race |
| CVE-2026-98258 | 7.8 HIGH | posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list |
| CVE-2026-98254 | 7.8 HIGH | swiotlb: use the adjusted address for the highmem page lookup |
Showing top 20 of 208 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
Same vendor: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
V. Comments for CVE-2026-98302
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