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CVE-2026-45865

📛 CVE Title

mctp i2c: initialise event handler read bytes

⬇ Download JSON ⚠ View as Threat

Description

In the Linux kernel, the following vulnerability has been resolved: mctp i2c: initialise event handler read bytes Set a 0xff value for i2c reads of an mctp-i2c device. Otherwise reads will return "val" from the i2c bus driver. For i2c-aspeed and i2c-npcm7xx that is a stack uninitialised u8. Tested with "i2ctransfer -y 1 r10@0x34" where 0x34 is a mctp-i2c instance, now it returns all 0xff.

Overview

State
PUBLISHED
Assigner (CNA)
Linux
CVSS severity
high
CVSS score
CVSS 7.1 / 10 7.1 7.1 / 10
CVSS vector
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Effective score
7.1 / 10 HIGH source: CNA overview
CWE(s)
—
Reserved
2026-05-13
Published
2026-05-27 12:15 UTC
Last updated
2026-05-27 12:15 UTC
Source
https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/45xxx/CVE-2026-45865.json
Linked Threat
CVE-2026-45865 — CVE-2026-45865

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published
2026-05-27 14:16:58 UTC
NVD last modified
2026-06-25 21:07:04 UTC
NVD CVSS v3.1
CVSS 5.5 / 10 5.5 5.5 / 10 MEDIUM source: nvd@nist.gov
NVD CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Exploitability subscore
1.8 / 10
Impact subscore
3.6 / 10
EPSS score
0.0016 (probability of exploitation in next 30 days)
EPSS percentile
5.17% vs all CVEs — higher = more likely to be exploited, as of 2026-07-26

NVD / KEV / EPSS data refreshed 2026-07-27 10:53 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID
EUVD-2026-32331
Assigner
Linux
Published
May 27, 2026, 12:15:45 PM
Updated
May 27, 2026, 12:15:45 PM
EUVD base score
0.0 / 10
EUVD-reported EPSS
0.1600
Vendors
Linux
Products
Linux (patch: 6.19.4)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <fa9861e5c8af7651dddfa8d490aaada17ae33b6c)
Linux (patch: 7.0)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <93e01e837e105299f1c259ef71f6e1ec4fe806e3)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <1eeedb310229bfee9dd4d992e5bba33fe1378a8f)
Linux (patch: 6.12.75)
Linux (patch: 6.18.14)
Linux (5.18)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <2a14e91b6d76639dac70ea170f4384c1ee3cb48d)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <6ff2ebfef75fbc57d937d8fbe738b967edf2d331)
Linux (patch: 0)
Linux (f5b8abf9fc3dacd7529d363e26fe8230935d65f8 <11f83253244060b5de5eac787f61ae3f3e559d01)
Linux (patch: 6.1.165)
Linux (patch: 6.6.128)
Aliases
GHSA-6j35-qr59-823q

ENISA description: In the Linux kernel, the following vulnerability has been resolved: mctp i2c: initialise event handler read bytes Set a 0xff value for i2c reads of an mctp-i2c device. Otherwise reads will return "val" from the i2c bus driver. For i2c-aspeed and i2c-npcm7xx that is a stack uninitialised u8. Tested with "i2ctransfer -y 1 r10@0x34" where 0x34 is a mctp-i2c instance, now it returns all 0xff.

EUVD references (6)

Affected products (2)
VendorProductVersionsPlatforms
Linux Linux f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected), f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected), f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected), f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected), f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected), f5b8abf9fc3dacd7529d363e26fe8230935d65f8 (affected) —
Linux Linux 5.18 (affected), 0 (unaffected), 6.1.165 (unaffected), 6.6.128 (unaffected), 6.12.75 (unaffected), 6.18.14 (unaffected), 6.19.4 (unaffected), 7.0 (unaffected) —

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor references (6)

References embedded in the original CVE record by the assigning CNA.

Web references (9)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

NVD-tagged references (6)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

Remediations (17)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-45865.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/mctp/mctp-i2c.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "93e01e837e105299f1c259ef71f6e1ec4fe806e3",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            },
            {
              "lessThan": "11f83253244060b5de5eac787f61ae3f3e559d01",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            },
            {
              "lessThan": "fa9861e5c8af7651dddfa8d490aaada17ae33b6c",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            },
            {
              "lessThan": "6ff2ebfef75fbc57d937d8fbe738b967edf2d331",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            },
            {
              "lessThan": "1eeedb310229bfee9dd4d992e5bba33fe1378a8f",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            },
            {
              "lessThan": "2a14e91b6d76639dac70ea170f4384c1ee3cb48d",
              "status": "affected",
              "version": "f5b8abf9fc3dacd7529d363e26fe8230935d65f8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/mctp/mctp-i2c.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.128",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.165",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.128",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.14",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.4",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmctp i2c: initialise event handler read bytes\n\nSet a 0xff value for i2c reads of an mctp-i2c device. Otherwise reads\nwill return \"val\" from the i2c bus driver. For i2c-aspeed and\ni2c-npcm7xx that is a stack uninitialised u8.\n\nTested with \"i2ctransfer -y 1 r10@0x34\" where 0x34 is a mctp-i2c\ninstance, now it returns all 0xff."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:15:45.082Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/93e01e837e105299f1c259ef71f6e1ec4fe806e3"
        },
        {
          "url": "https://git.kernel.org/stable/c/11f83253244060b5de5eac787f61ae3f3e559d01"
        },
        {
          "url": "https://git.kernel.org/stable/c/fa9861e5c8af7651dddfa8d490aaada17ae33b6c"
        },
        {
          "url": "https://git.kernel.org/stable/c/6ff2ebfef75fbc57d937d8fbe738b967edf2d331"
        },
        {
          "url": "https://git.kernel.org/stable/c/1eeedb310229bfee9dd4d992e5bba33fe1378a8f"
        },
        {
          "url": "https://git.kernel.org/stable/c/2a14e91b6d76639dac70ea170f4384c1ee3cb48d"
        }
      ],
      "title": "mctp i2c: initialise event handler read bytes",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45865",
    "datePublished": "2026-05-27T12:15:45.082Z",
    "dateReserved": "2026-05-13T15:03:33.080Z",
    "dateUpdated": "2026-05-27T12:15:45.082Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}