CVE-2026-63962 (GCVE-0-2026-63962)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-07-20 06:41
VLAI
Title
usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes() svdm_consume_modes() checks pmdata->altmodes against the array size once before the loop over the count, but forgot to check the bound at every point in the loop. In the well-behaved SVDM discovery flow this is harmless because each of at most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX modes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX]. But the CMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming ACK with any request the port actually sent. Once port->partner is set, an unsolicited Discover Modes ACK is consumed unconditionally. A broken or malicious port partner can therefore drive altmodes to ALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra Discover Modes ACK with seven VDOs. Because the pre-loop check passes, the loop could then writes up to five entries past altmode_desc[]. For mode_data_prime the next field in struct tcpm_port is the partner_altmode[] pointer array, which then receives partner-chosen SVID/VDO bytes. Move the bound check inside the loop so the array can never be indexed past ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner supplies or how the function was reached.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4ab8c18d4d67321cc7b660559de17511d4fc0237 , < 845598b154b9a92e9d279fafafa9405c121ae805 (git)
Affected: 4ab8c18d4d67321cc7b660559de17511d4fc0237 , < 4505f33dab56c274e82f47f94bf60a8cbf8f4b42 (git)
Affected: 4ab8c18d4d67321cc7b660559de17511d4fc0237 , < cbad85b446c06adbc5e5bed565871bb918ce9d32 (git)
Affected: 4ab8c18d4d67321cc7b660559de17511d4fc0237 , < 3389c149c68c3fea61910ad5d34f7bf3bff44e32 (git)
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Linux Linux Affected: 4.19
Unaffected: 0 , < 4.19 (semver)
Unaffected: 6.12.93 , ≤ 6.12.* (semver)
Unaffected: 6.18.35 , ≤ 6.18.* (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/typec/tcpm/tcpm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "845598b154b9a92e9d279fafafa9405c121ae805",
              "status": "affected",
              "version": "4ab8c18d4d67321cc7b660559de17511d4fc0237",
              "versionType": "git"
            },
            {
              "lessThan": "4505f33dab56c274e82f47f94bf60a8cbf8f4b42",
              "status": "affected",
              "version": "4ab8c18d4d67321cc7b660559de17511d4fc0237",
              "versionType": "git"
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              "status": "affected",
              "version": "4ab8c18d4d67321cc7b660559de17511d4fc0237",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "4ab8c18d4d67321cc7b660559de17511d4fc0237",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/typec/tcpm/tcpm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.19"
            },
            {
              "lessThan": "4.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.93",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.35",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.12",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()\n\nsvdm_consume_modes() checks pmdata-\u003ealtmodes against the array size once\nbefore the loop over the count, but forgot to check the bound at every\npoint in the loop.\n\nIn the well-behaved SVDM discovery flow this is harmless because each of\nat most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX\nmodes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX].  But the\nCMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming\nACK with any request the port actually sent.  Once port-\u003epartner is set,\nan unsolicited Discover Modes ACK is consumed unconditionally.  A broken\nor malicious port partner can therefore drive altmodes to\nALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra\nDiscover Modes ACK with seven VDOs.  Because the pre-loop check passes,\nthe loop could then writes up to five entries past altmode_desc[].  For\nmode_data_prime the next field in struct tcpm_port is the\npartner_altmode[] pointer array, which then receives partner-chosen\nSVID/VDO bytes.\n\nMove the bound check inside the loop so the array can never be indexed\npast ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner\nsupplies or how the function was reached."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T06:41:42.766Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/845598b154b9a92e9d279fafafa9405c121ae805"
        },
        {
          "url": "https://git.kernel.org/stable/c/4505f33dab56c274e82f47f94bf60a8cbf8f4b42"
        },
        {
          "url": "https://git.kernel.org/stable/c/cbad85b446c06adbc5e5bed565871bb918ce9d32"
        },
        {
          "url": "https://git.kernel.org/stable/c/3389c149c68c3fea61910ad5d34f7bf3bff44e32"
        }
      ],
      "title": "usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63962",
    "datePublished": "2026-07-19T14:55:51.682Z",
    "dateReserved": "2026-07-19T07:54:57.024Z",
    "dateUpdated": "2026-07-20T06:41:42.766Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63962",
      "date": "2026-09-21",
      "epss": "0.00206",
      "percentile": "0.10917"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-13T00:01:37.000Z",
      "cve": "CVE-2026-63962",
      "id": "msrc_CVE-2026-63962",
      "initial_release_date": "2026-07-21T01:02:25.000Z",
      "product_status:known_affected": "1",
      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63962.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/usb/typec/tcpm/tcpm.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "versionType": "git"
                  },
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                    "versionType": "git"
                  },
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                    "status": "affected",
                    "version": "4ab8c18d4d67321cc7b660559de17511d4fc0237",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "drivers/usb/typec/tcpm/tcpm.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "4.19"
                  },
                  {
                    "lessThan": "4.19",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.93",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.35",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.0.*",
                    "status": "unaffected",
                    "version": "7.0.12",
                    "versionType": "semver"
                  },
                  {
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                    "version": "7.1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()\n\nsvdm_consume_modes() checks pmdata-\u003ealtmodes against the array size once\nbefore the loop over the count, but forgot to check the bound at every\npoint in the loop.\n\nIn the well-behaved SVDM discovery flow this is harmless because each of\nat most SVID_DISCOVERY_MAX SVIDs contributes at most MODE_DISCOVERY_MAX\nmodes, exactly filling altmode_desc[ALTMODE_DISCOVERY_MAX].  But the\nCMDT_RSP_ACK handler in tcpm_pd_svdm() does not correlate an incoming\nACK with any request the port actually sent.  Once port-\u003epartner is set,\nan unsolicited Discover Modes ACK is consumed unconditionally.  A broken\nor malicious port partner can therefore drive altmodes to\nALTMODE_DISCOVERY_MAX - 1 via the normal flow, and then send one extra\nDiscover Modes ACK with seven VDOs.  Because the pre-loop check passes,\nthe loop could then writes up to five entries past altmode_desc[].  For\nmode_data_prime the next field in struct tcpm_port is the\npartner_altmode[] pointer array, which then receives partner-chosen\nSVID/VDO bytes.\n\nMove the bound check inside the loop so the array can never be indexed\npast ALTMODE_DISCOVERY_MAX regardless of how many VDOs the partner\nsupplies or how the function was reached."
          }
        ],
        "id": "CVE-2026-63962",
        "lastModified": "2026-07-30T14:51:11.223",
        "metrics": {},
        "published": "2026-07-19T16:17:15.163",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3389c149c68c3fea61910ad5d34f7bf3bff44e32"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4505f33dab56c274e82f47f94bf60a8cbf8f4b42"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/845598b154b9a92e9d279fafafa9405c121ae805"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/cbad85b446c06adbc5e5bed565871bb918ce9d32"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-07T13:43:59+00:00",
      "cve": "CVE-2026-63962",
      "id": "CVE-2026-63962",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "43",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: usb: typec: tcpm: bound altmode_desc[] per iteration in svdm_consume_modes()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63962.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-18T00:45:45Z",
      "cve": "CVE-2026-63962",
      "id": "CVE-2026-63962",
      "initial_release_date": "2026-07-21T13:02:40Z",
      "product_status:first_fixed": "25",
      "product_status:known_affected": "698",
      "product_status:known_not_affected": "23",
      "product_status:recommended": "250",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63962",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63962.json",
      "version": "13"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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