ghsa-v7fr-3jhm-3qhw
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
comedi: Make insn_rw_emulate_bits() do insn->n samples
The insn_rw_emulate_bits() function is used as a default handler for
INSN_READ instructions for subdevices that have a handler for
INSN_BITS but not for INSN_READ. Similarly, it is used as a default
handler for INSN_WRITE instructions for subdevices that have a handler
for INSN_BITS but not for INSN_WRITE. It works by emulating the
INSN_READ or INSN_WRITE instruction handling with a constructed
INSN_BITS instruction. However, INSN_READ and INSN_WRITE
instructions are supposed to be able read or write multiple samples,
indicated by the insn->n value, but insn_rw_emulate_bits() currently
only handles a single sample. For INSN_READ, the comedi core will
copy insn->n samples back to user-space. (That triggered KASAN
kernel-infoleak errors when insn->n was greater than 1, but that is
being fixed more generally elsewhere in the comedi core.)
Make insn_rw_emulate_bits() either handle insn->n samples, or return
an error, to conform to the general expectation for INSN_READ and
INSN_WRITE handlers.
{
"affected": [],
"aliases": [
"CVE-2025-39686"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-05T18:15:45Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: Make insn_rw_emulate_bits() do insn-\u003en samples\n\nThe `insn_rw_emulate_bits()` function is used as a default handler for\n`INSN_READ` instructions for subdevices that have a handler for\n`INSN_BITS` but not for `INSN_READ`. Similarly, it is used as a default\nhandler for `INSN_WRITE` instructions for subdevices that have a handler\nfor `INSN_BITS` but not for `INSN_WRITE`. It works by emulating the\n`INSN_READ` or `INSN_WRITE` instruction handling with a constructed\n`INSN_BITS` instruction. However, `INSN_READ` and `INSN_WRITE`\ninstructions are supposed to be able read or write multiple samples,\nindicated by the `insn-\u003en` value, but `insn_rw_emulate_bits()` currently\nonly handles a single sample. For `INSN_READ`, the comedi core will\ncopy `insn-\u003en` samples back to user-space. (That triggered KASAN\nkernel-infoleak errors when `insn-\u003en` was greater than 1, but that is\nbeing fixed more generally elsewhere in the comedi core.)\n\nMake `insn_rw_emulate_bits()` either handle `insn-\u003en` samples, or return\nan error, to conform to the general expectation for `INSN_READ` and\n`INSN_WRITE` handlers.",
"id": "GHSA-v7fr-3jhm-3qhw",
"modified": "2025-09-05T18:31:26Z",
"published": "2025-09-05T18:31:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39686"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7afba9221f70d4cbce0f417c558879cba0eb5e66"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/842f307a1d115b24f2bcb2415c4e344f11f55930"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/92352ed2f9ac422181e381c2430c2d0dfb46faa0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ab77e85bd3bc006ef40738f26f446a660813da44"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ae8bc1f07bcb31b8636420e03d1f9c3df6219a2b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dc0a2f142d655700db43de90cb6abf141b73d908"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.