Linux Kernel HWMon: ADM1266 PMBus Buffer Overflow (CVE-2026-64085)
CVE-2026-64085 Published on July 19, 2026
hwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer
In 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.
Products Associated with CVE-2026-64085
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Affected Versions
Linux:- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 7896d87cbb05e097efc113243d4e38f9f8cea16c is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 9d5309500b4607b7198e19f0a3fa13eb864cd5fb is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 6098634cfa711f11a8d65368dc51ec8f7c8241ba is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 60c4b9fe1a3dd012014b1f561a6928a0b5db1126 is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 83e039f0a43e0708515b0479cb7690fb93faaaa0 is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 97a9cf2a8217ca1cdaf48cb9ab26e471632c7e7f is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below dd47b8c4a0a8ced442da3f008db28fbbd31feaf0 is affected.
- Version 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and below 43cae21424ff8e33894a0f86c6b80b840c049fd7 is affected.
- Version 5.10 is affected.
- Before 5.10 is unaffected.
- Version 5.10.258, <= 5.10.* is unaffected.
- Version 5.15.209, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.