GHSA-8Q8M-4RRF-VCV4
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-19 18:31In the Linux kernel, the following vulnerability has been resolved:
hwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer
adm1266_pmbus_block_xfer() copies the device-supplied block payload into the caller-provided buffer using the device-supplied length:
memcpy(data_r, &msgs[1].buf[1], msgs[1].buf[0]);
The helper does not know how large data_r is and trusts the device to return at most one record's worth of bytes. adm1266_nvmem_read_blackbox() violates that contract: it advances read_buff inside data->dev_mem in ADM1266_BLACKBOX_SIZE (64-byte) strides while the helper is willing to write up to ADM1266_PMBUS_BLOCK_MAX (255) bytes. A device that returns more than 64 bytes on the trailing record (read_buff offset 1984 in the 2048-byte dev_mem allocation) overflows dev_mem by up to 191 bytes before the post-call
if (ret != ADM1266_BLACKBOX_SIZE)
return -EIO;
can reject the response.
Contain the fix in the caller without changing the helper signature: read each record into a 255-byte local bounce buffer that matches the helper's maximum output, validate the returned length, and only then copy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot.
{
"affected": [],
"aliases": [
"CVE-2026-64085"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:49Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer\n\nadm1266_pmbus_block_xfer() copies the device-supplied block payload\ninto the caller-provided buffer using the device-supplied length:\n\n\tmemcpy(data_r, \u0026msgs[1].buf[1], msgs[1].buf[0]);\n\nThe helper does not know how large data_r is and trusts the device to\nreturn at most one record\u0027s worth of bytes. adm1266_nvmem_read_blackbox()\nviolates that contract: it advances read_buff inside data-\u003edev_mem in\nADM1266_BLACKBOX_SIZE (64-byte) strides while the helper is willing to\nwrite up to ADM1266_PMBUS_BLOCK_MAX (255) bytes. A device that returns\nmore than 64 bytes on the trailing record (read_buff offset 1984 in\nthe 2048-byte dev_mem allocation) overflows dev_mem by up to 191 bytes\nbefore the post-call\n\n\tif (ret != ADM1266_BLACKBOX_SIZE)\n\t\treturn -EIO;\n\ncan reject the response.\n\nContain the fix in the caller without changing the helper signature:\nread each record into a 255-byte local bounce buffer that matches the\nhelper\u0027s maximum output, validate the returned length, and only then\ncopy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot.",
"id": "GHSA-8q8m-4rrf-vcv4",
"modified": "2026-07-19T18:31:51Z",
"published": "2026-07-19T18:31:51Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64085"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/43cae21424ff8e33894a0f86c6b80b840c049fd7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6098634cfa711f11a8d65368dc51ec8f7c8241ba"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/60c4b9fe1a3dd012014b1f561a6928a0b5db1126"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7896d87cbb05e097efc113243d4e38f9f8cea16c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/83e039f0a43e0708515b0479cb7690fb93faaaa0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/97a9cf2a8217ca1cdaf48cb9ab26e471632c7e7f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9d5309500b4607b7198e19f0a3fa13eb864cd5fb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dd47b8c4a0a8ced442da3f008db28fbbd31feaf0"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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