CVE-2025-39680 (GCVE-0-2025-39680)

Vulnerability from cvelistv5 – Published: 2025-09-05 17:20 – Updated: 2026-08-05 12:04
VLAI
Title
i2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer
Summary
In the Linux kernel, the following vulnerability has been resolved: i2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer The data->block[0] variable comes from user. Without proper check, the variable may be very large to cause an out-of-bounds bug. Fix this bug by checking the value of data->block[0] first. 1. commit 39244cc75482 ("i2c: ismt: Fix an out-of-bounds bug in ismt_access()") 2. commit 92fbb6d1296f ("i2c: xgene-slimpro: Fix out-of-bounds bug in xgene_slimpro_i2c_xfer()")
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7056 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c366be720235301fdadf67e6f1ea6ff32669c074 , < 071e43fcba5ddd9a7813e6cc0aa10299eae41b21 (git)
Affected: c366be720235301fdadf67e6f1ea6ff32669c074 , < 57f312b955938fc4663f430cb57a71f2414f601b (git)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.16.4 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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              "value": "AV:L - The vulnerable code is reached only through the `I2C_SMBUS` ioctl on a local `/dev/i2c-N` character device (`i2cdev_ioctl_smbus` \u2192 `i2c_smbus_xfer` \u2192 `rtl9300_i2c_smbus_xfer`). There is no network or remote-peer path into this driver.\nAC:L - A single ioctl with an attacker-chosen `data-\u003eblock[0]` deterministically drives the unvalidated length into `rtl9300_i2c_config_xfer()` and the transfer helpers; there is no race, timing window, or memory-layout condition outside the attacker\u0027s control.\nPR:L - `i2cdev_open()` and `i2cdev_ioctl()` contain no `capable()`/`CAP_*` check whatsoever \u2014 reachability depends purely on `/dev/i2c-*` node permissions, which embedded, switch, and Android-style images commonly grant to a non-root `i2c` group. Matches the PR:L used for the analogous CVE-2026-64191 and CVE-2026-31627.\nUI:N - The attacker triggers the flaw entirely on their own with one ioctl on an already-present device node; no victim action, mount, or file-open is needed.\nS:U - The unvalidated length is consumed within the kernel\u0027s own memory and the SoC\u0027s I\u00b2C controller registers, all under the same security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The unchecked user-supplied length propagates to out-of-bounds reads past the 34-byte `union i2c_smbus_data` on the caller\u0027s stack (via `trace_smbus_write()` on the shared path, and via `i2c_smbus_read_block_data()`\u0027s `memcpy` of the driver-overwritten `block[0]`), exposing adjacent kernel stack contents.\nI:H - The same value reaches an out-of-bounds write context \u2014 `i2c_smbus_read_block_data()` copies a length of up to 255 into a 32-byte caller buffer \u2014 and the `(len - 1) \u0026 0xf` underflow programs unintended hardware writes, which the same-driver CVE-2025-39928 documents as destructive (overwriting SFP EEPROM contents).\nA:H - Out-of-bounds stack access of this kind produces oopses/panics under KASAN or on corrupted stack state, and the spurious 16-byte hardware transfer can permanently brick attached I\u00b2C peripherals, denying service to the device."
            }
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/071e43fcba5ddd9a7813e6cc0aa10299eae41b21"
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          "url": "https://git.kernel.org/stable/c/57f312b955938fc4663f430cb57a71f2414f601b"
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      "title": "i2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer",
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    "cveId": "CVE-2025-39680",
    "datePublished": "2025-09-05T17:20:46.456Z",
    "dateReserved": "2025-04-16T07:20:57.112Z",
    "dateUpdated": "2026-08-05T12:04:30.326Z",
    "state": "PUBLISHED"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer\n\nThe data-\u003eblock[0] variable comes from user. Without proper check,\nthe variable may be very large to cause an out-of-bounds bug.\n\nFix this bug by checking the value of data-\u003eblock[0] first.\n\n1. commit 39244cc75482 (\"i2c: ismt: Fix an out-of-bounds bug in\n   ismt_access()\")\n2. commit 92fbb6d1296f (\"i2c: xgene-slimpro: Fix out-of-bounds bug in\n   xgene_slimpro_i2c_xfer()\")"
          },
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            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ni2c: rtl9300: Correcci\u00f3n de un error de fuera de l\u00edmites en rtl9300_i2c_smbus_xfer\n\nLa variable data-\u003eblock[0] proviene del usuario. Sin una verificaci\u00f3n adecuada,\nla variable puede ser muy grande para causar un error de fuera de l\u00edmites.\n\nCorrige este error verificando primero el valor de data-\u003eblock[0].\n\n1. commit 39244cc75482 (\u0027i2c: ismt: Correcci\u00f3n de un error de fuera de l\u00edmites en\n   ismt_access()\u0027)\n2. commit 92fbb6d1296f (\u0027i2c: xgene-slimpro: Correcci\u00f3n de un error de fuera de l\u00edmites en\n   xgene_slimpro_i2c_xfer()\u0027)"
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        "id": "CVE-2025-39680",
        "lastModified": "2026-10-19T21:10:00.160",
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              "source": "nvd@nist.gov",
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        "published": "2025-09-05T18:15:44.420",
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            "tags": [
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        "vulnStatus": "Modified",
        "weaknesses": [
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                "lang": "en",
                "value": "CWE-125"
              }
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            "type": "Primary"
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      "current_release_date": "2026-06-30T10:26:53+00:00",
      "cve": "CVE-2025-39680",
      "id": "CVE-2025-39680",
      "initial_release_date": "2025-09-05T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: i2c: rtl9300: Fix out-of-bounds bug in rtl9300_i2c_smbus_xfer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39680.json",
      "version": "3"
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}



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