In the Linux kernel, the following vulnerability has been resolved:

net: usb: lan78xx: Fix lost EEPROM read timeout error(-ETIMEDOUT) in lan78xx_read_raw_eeprom

Syzbot reported read of uninitialized variable BUG with following call stack.

lan78xx 8-1:1.0 (unnamed net_device) (uninitialized): EEPROM read operation timeout
=====================================================
BUG: KMSAN: uninit-value in lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline]
BUG: KMSAN: uninit-value in lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]
BUG: KMSAN: uninit-value in lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241
lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline]
lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]
lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241
lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766
lan78xx_probe+0x225c/0x3310 drivers/net/usb/lan78xx.c:4707

Local variable sig.i.i created at:
lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1092 [inline]
lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]
lan78xx_reset+0x77e/0x2cd0 drivers/net/usb/lan78xx.c:3241
lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766

The function lan78xx_read_raw_eeprom failed to properly propagate EEPROM
read timeout errors (-ETIMEDOUT). In the fallthrough path, it first
attempted to restore the pin configuration for LED outputs and then
returned only the status of that restore operation, discarding the
original timeout error.

As a result, callers could mistakenly treat the data buffer as valid
even though the EEPROM read had actually timed out with no data or partial
data.

To fix this, handle errors in restoring the LED pin configuration separately.
If the restore succeeds, return any prior EEPROM timeout error correctly
to the caller.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00018.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors Products
Linux
  • Linux Kernel
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/49bdb63ff64469a6de8ea901aef123c75be9bbe7 cve-icon cve-icon
https://git.kernel.org/stable/c/a72a7c4f675080a324d4c2167bd2314d968279f1 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025111244-CVE-2025-40189-c4ca@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-40189 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-40189 cve-icon
History

Fri, 14 Nov 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Thu, 13 Nov 2025 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Wed, 12 Nov 2025 22:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: usb: lan78xx: Fix lost EEPROM read timeout error(-ETIMEDOUT) in lan78xx_read_raw_eeprom Syzbot reported read of uninitialized variable BUG with following call stack. lan78xx 8-1:1.0 (unnamed net_device) (uninitialized): EEPROM read operation timeout ===================================================== BUG: KMSAN: uninit-value in lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline] BUG: KMSAN: uninit-value in lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] BUG: KMSAN: uninit-value in lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline] lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766 lan78xx_probe+0x225c/0x3310 drivers/net/usb/lan78xx.c:4707 Local variable sig.i.i created at: lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1092 [inline] lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] lan78xx_reset+0x77e/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766 The function lan78xx_read_raw_eeprom failed to properly propagate EEPROM read timeout errors (-ETIMEDOUT). In the fallthrough path, it first attempted to restore the pin configuration for LED outputs and then returned only the status of that restore operation, discarding the original timeout error. As a result, callers could mistakenly treat the data buffer as valid even though the EEPROM read had actually timed out with no data or partial data. To fix this, handle errors in restoring the LED pin configuration separately. If the restore succeeds, return any prior EEPROM timeout error correctly to the caller.
Title net: usb: lan78xx: Fix lost EEPROM read timeout error(-ETIMEDOUT) in lan78xx_read_raw_eeprom
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-11-12T21:56:30.575Z

Reserved: 2025-04-16T07:20:57.177Z

Link: CVE-2025-40189

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-11-12T22:15:45.833

Modified: 2025-11-14T16:42:30.503

Link: CVE-2025-40189

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-11-12T00:00:00Z

Links: CVE-2025-40189 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-11-13T09:52:24Z