n the Linux kernel, the following vulnerability has been resolved: i2c: rtl9300: ensure data length is within supported range Add an explicit check for the xfer length to 'rtl9300_i2c_config_xfer' to ensure the data length isn't within the supported range. In particular a data length of 0 is not supported by the hardware and causes unintended or destructive behaviour. This limitation becomes obvious when looking at the register documentation [1]. 4 bits are reserved for DATA_WIDTH and the value of these 4 bits is used as N + 1, allowing a data length range of 1 <= len <= 16. Affected by this is the SMBus Quick Operation which works with a data length of 0. Passing 0 as the length causes an underflow of the value due to: (len - 1) & 0xf and effectively specifying a transfer length of 16 via the registers. This causes a 16-byte write operation instead of a Quick Write. For example, on SFP modules without write-protected EEPROM this soft-bricks them by overwriting some initial bytes. For completeness, also add a quirk for the zero length. [1] https://svanheule.net/realtek/longan/register/i2c_mst1_ctrl2
Configuration 1 (hide)
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10 Dec 2025, 21:50
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* |
|
| CWE | CWE-191 | |
| References | () https://git.kernel.org/stable/c/06418cb5a1a542a003fdb4ad8e76ea542d57cfba - Patch | |
| References | () https://git.kernel.org/stable/c/c91382328fc89f73144d5582f2d8f1dd3e41c8f7 - Patch | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux linux Kernel
Linux |
02 Oct 2025, 19:12
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Published : 2025-10-01 08:15
Updated : 2026-01-14 18:16
NVD link : CVE-2025-39928
Mitre link : CVE-2025-39928
CVE.ORG link : CVE-2025-39928
JSON object : View
Integer Underflow (Wrap or Wraparound)