# CVE-2025-40189: linux: In the Linux kernel, the following vulnerability has been resolved:  net: usb: lan78xx: Fix lost EEPROM read timeout...

CVE-2025-40189 is fixed in linux on 1 platform by DEBIAN-CVE-2025-40189 (version 6.17.6-1), released November 12, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-40189
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 12, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.17.6-1 | [DEBIAN-CVE-2025-40189](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40189.md) | Nov 12, 2025 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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