CVE-2026-93287— i2c: smbus: reject oversized block transfers in the common path
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，已解决以下漏洞： i2c: smbus：在通用路径中拒绝过大的块传输 SMBus 块传输长度数据 在 中进行了验证，但该检查执行得太晚，无法阻止跟踪点（tracepoints），并且当适配器提供原生的 实现时，该检查会被完全跳过。这导致用户可控的过大块长度未经检查地进入跟踪点的 调用和驱动程序回调。 在 中添加早期验证，在触发任何跟踪点或运行任何驱动程序回调之前，拒绝调用者提供的长度为零或超过 的块传输。由于 是在 SMBus 块读取时由设备填充的，因此该检查仅限于长度实际由调用者提供的操作
Possible ATT&CK Techniques 1 AI
T1068 · Exploitation for Privilege EscalationAffected Version Matrix 16
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 4710317891e4824ce1510a6b5066abbd3e917750< 856dffcc097b3d8ed45a643ebda07cb92968cb33 |
affected |
4710317891e4824ce1510a6b5066abbd3e917750< 356875e33f2c6d2061a02c9dec1a1e639d265a55 |
affected | ||
4710317891e4824ce1510a6b5066abbd3e917750< 72ca5e0b8b7a62615758f8871c34d61616c2dc8b |
affected | ||
4710317891e4824ce1510a6b5066abbd3e917750< df077253f6405d67ad087538e495ef32a05717b7 |
affected | ||
4710317891e4824ce1510a6b5066abbd3e917750< f09edffba97d37b1fdff5f818a9a45f8a98ac171 |
affected | ||
4710317891e4824ce1510a6b5066abbd3e917750< c4b478bc50b7ca9865e237909941253a0f7111a2 |
affected | ||
4710317891e4824ce1510a6b5066abbd3e917750< 3051cd060fa496df42954291fa2306ed2eab4ecc |
affected | ||
2.6.33 |
affected | ||
| … +8 more rows | |||
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I. Basic Information for CVE-2026-93287
Vulnerability Information
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Vulnerability Title
i2c: smbus: reject oversized block transfers in the common path
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
i2c: smbus: reject oversized block transfers in the common path
The SMBus block transfer length data->block[0] is validated in
i2c_smbus_xfer_emulated() but that check runs too late for tracepoints
and is skipped entirely when the adapter provides a native smbus_xfer
implementation. This allows user-controlled oversized block lengths to
reach tracepoint memcpy calls and driver callbacks unchecked.
Add an early validation in __i2c_smbus_xfer() that rejects block
transfers whose caller-supplied length is zero or exceeds
I2C_SMBUS_BLOCK_MAX before any tracepoint fires or driver callback
runs. data->block[0] is filled in by the device on SMBus block reads,
so the check is scoped to operations where the length is actually
supplied by the caller. This is consistent with the existing -EINVAL
convention in the emulated path and protects all downstream consumers
at once: the smbus_write tracepoint, all native smbus_xfer driver
implementations, and the emulated path.
Two distinct bugs are fixed by this change:
Bug 1: smbus_write tracepoint OOB (include/trace/events/smbus.h)
trace_smbus_write() fires before any validation and copies
data->block[0]+1 bytes into a 34-byte event buffer. With
block[0]=0xfe the tracepoint copies 255 bytes, overflowing by 221.
BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_smbus_write+0x27c/0x530
Read of size 255 at addr ffff88800d98fcf8 by task poc_smbus/91
Call Trace:
<TASK>
__asan_memcpy+0x23/0x80
trace_event_raw_event_smbus_write+0x27c/0x530
__i2c_smbus_xfer+0x43a/0xa40
i2c_smbus_xfer+0x19e/0x340
i2cdev_ioctl_smbus+0x38f/0x7f0
i2cdev_ioctl+0x35e/0x680
__x64_sys_ioctl+0x147/0x1e0
do_syscall_64+0xcf/0x15a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
Bug 2: i2c-stub I2C_SMBUS_I2C_BLOCK_DATA OOB (drivers/i2c/i2c-stub.c)
stub_xfer() implements .smbus_xfer directly and only clamps
block[0] against 256-command, not I2C_SMBUS_BLOCK_MAX. With
block[0]=0xff and command=0 the loop accesses block[1+i] for
i up to 254, far past the 34-byte union.
UBSAN: array-index-out-of-bounds in drivers/i2c/i2c-stub.c:223:44
index 34 is out of range for type '__u8 [34]'
Call Trace:
<TASK>
__ubsan_handle_out_of_bounds+0xd7/0x120
stub_xfer+0x1971/0x198f [i2c_stub]
__i2c_smbus_xfer+0x306/0xa40
i2c_smbus_xfer+0x19e/0x340
i2cdev_ioctl_smbus+0x38f/0x7f0
i2cdev_ioctl+0x35e/0x680
__x64_sys_ioctl+0x147/0x1e0
do_syscall_64+0xcf/0x15a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
Both traces reproduced on v7.0-rc6+i2c/for-current with KASAN+UBSAN.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-93287
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-93287 (7)
Same Patch Batch · Linux · 2026-09-24 · 234 CVEs total
| CVE-2026-93207 | 9.8 CRITICAL | SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry |
| CVE-2026-97413 | 9.8 CRITICAL | RDMA/rtrs-srv: Fix integer underflow in process_read and process_write |
| CVE-2026-93228 | 9.1 CRITICAL | svcrdma: Reject Write/Reply chunks with segcount 0 |
| CVE-2026-93793 | 8.8 HIGH | wifi: iwlwifi: mvm: validate TX_CMD response layout |
| CVE-2026-93799 | 8.8 HIGH | wifi: iwlwifi: mvm: validate sta_id in BA window status notif |
| CVE-2026-93790 | 8.8 HIGH | wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif |
| CVE-2026-93806 | 8.8 HIGH | wifi: cfg80211: validate assoc response length before status and IE access |
| CVE-2026-97442 | 8.8 HIGH | wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi |
| CVE-2026-97509 | 8.8 HIGH | thunderbolt: Keep XDomain reference during the lifetime of a service |
| CVE-2026-97409 | 8.8 HIGH | nvme-fc: Do not cancel requests in io target before it is initialized |
| CVE-2026-93280 | 8.8 HIGH | greybus: audio: bound the topology section sizes against the fetched size |
| CVE-2026-93284 | 8.8 HIGH | drm/pagemap: dma-unmap pages before handling migration errors |
| CVE-2026-97451 | 8.4 HIGH | ACPICA: Fix integer overflow in acpi_ex_opcode_3A_1T_1R() (mid_op) |
| CVE-2026-97455 | 8.4 HIGH | ACPICA: Fix use-after-free in acpi_ds_terminate_control_method() |
| CVE-2026-97452 | 8.4 HIGH | ACPICA: Prevent adding invalid references |
| CVE-2026-97450 | 8.4 HIGH | ACPICA: validate handler object type in two places |
| CVE-2026-93827 | 8.4 HIGH | virtio-fs: avoid double-free on failed queue setup |
| CVE-2026-97433 | 8.2 HIGH | nvme: validate FDP configuration descriptor sizes |
| CVE-2026-93786 | 8.1 HIGH | ksmbd: preserve VFS inherited POSIX ACL mask |
| CVE-2026-93282 | 8.1 HIGH | ksmbd: fix maximum allowed access checks |
Showing top 20 of 234 CVEs. View all on vendor page → →
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Same vendor: Linux
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CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
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bpf: Reject dev-bound-only programs on other devices -
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CVE-2026-98380
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