CVE-2025-40189
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.
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).
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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.
Detalles técnicos trazas, registros y código del informe original
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
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
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{
"id": "CVE-2025-40189",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "8b1b2ca83b200fa46fdfb81e80ad5fe34537e6d4",
"lessThan": "a72a7c4f675080a324d4c2167bd2314d968279f1",
"versionType": "git"
},
{
"status": "affected",
"version": "8b1b2ca83b200fa46fdfb81e80ad5fe34537e6d4",
"lessThan": "49bdb63ff64469a6de8ea901aef123c75be9bbe7",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/usb/lan78xx.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.17.4",
"versionType": "semver",
"lessThanOrEqual": "6.17.*"
},
{
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/usb/lan78xx.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-11-12T22:15:45.833",
"references": [
{
"url": "https://git.kernel.org/stable/c/49bdb63ff64469a6de8ea901aef123c75be9bbe7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a72a7c4f675080a324d4c2167bd2314d968279f1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: usb: lan78xx: Fix lost EEPROM read timeout error(-ETIMEDOUT) in lan78xx_read_raw_eeprom\n\nSyzbot reported read of uninitialized variable BUG with following call stack.\n\nlan78xx 8-1:1.0 (unnamed net_device) (uninitialized): EEPROM read operation timeout\n=====================================================\nBUG: KMSAN: uninit-value in lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline]\nBUG: KMSAN: uninit-value in lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]\nBUG: KMSAN: uninit-value in lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241\n lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline]\n lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]\n lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241\n lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766\n lan78xx_probe+0x225c/0x3310 drivers/net/usb/lan78xx.c:4707\n\nLocal variable sig.i.i created at:\n lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1092 [inline]\n lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline]\n lan78xx_reset+0x77e/0x2cd0 drivers/net/usb/lan78xx.c:3241\n lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766\n\nThe function lan78xx_read_raw_eeprom failed to properly propagate EEPROM\nread timeout errors (-ETIMEDOUT). In the fallthrough path, it first\nattempted to restore the pin configuration for LED outputs and then\nreturned only the status of that restore operation, discarding the\noriginal timeout error.\n\nAs a result, callers could mistakenly treat the data buffer as valid\neven though the EEPROM read had actually timed out with no data or partial\ndata.\n\nTo fix this, handle errors in restoring the LED pin configuration separately.\nIf the restore succeeds, return any prior EEPROM timeout error correctly\nto the caller."
}
],
"lastModified": "2026-06-17T09:21:25.843",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}