Vulnerability-Lookup

FKIE_CVE-2026-8718

Vulnerability from fkie_nvd - Published: 2026-08-10 23:16 - Updated: 2026-08-26 16:59

Severity

8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

Summary

tls_opt_dtls_peer_connection_id_value_get() in subsys/net/lib/sockets/sockets_tls.c, which handles getsockopt(SOL_TLS, TLS_DTLS_PEER_CID_VALUE), passed the caller-supplied optval directly to mbedtls_ssl_get_peer_cid() without verifying the buffer was at least MBEDTLS_SSL_CID_OUT_LEN_MAX (default 32) bytes. mbedtls_ssl_get_peer_cid() copies the peer-negotiated DTLS Connection ID (length 1..MBEDTLS_SSL_CID_OUT_LEN_MAX) into that buffer without a destination-size parameter, so a caller-supplied optlen smaller than the CID causes a write of up to 31 bytes past the buffer end. In CONFIG_USERSPACE builds the getsockopt syscall verifier (z_vrfy_zsock_getsockopt) bounce-buffers the user's optval into a kernel allocation of exactly optlen bytes (k_usermode_alloc_from_copy -> z_thread_malloc), so an unprivileged user thread that passes a small optlen on a connected DTLS socket with Connection ID enabled induces a kernel-heap buffer overflow, with the overflowing content being the remote peer's CID. The defect requires CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID, an established DTLS session with a negotiated peer CID, and (for the kernel-crossing case) CONFIG_USERSPACE. Introduced when the TLS_DTLS_CID option was added (v3.5.0). The fix rejects callers whose optlen is below MBEDTLS_SSL_CID_OUT_LEN_MAX with -EINVAL.

References

	URL	Tags
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/net/lib/sockets/sockets_tls.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.1",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vulnerabilities@zephyrproject.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "tls_opt_dtls_peer_connection_id_value_get() in subsys/net/lib/sockets/sockets_tls.c, which handles getsockopt(SOL_TLS, TLS_DTLS_PEER_CID_VALUE), passed the caller-supplied optval directly to mbedtls_ssl_get_peer_cid() without verifying the buffer was at least MBEDTLS_SSL_CID_OUT_LEN_MAX (default 32) bytes. mbedtls_ssl_get_peer_cid() copies the peer-negotiated DTLS Connection ID (length 1..MBEDTLS_SSL_CID_OUT_LEN_MAX) into that buffer without a destination-size parameter, so a caller-supplied optlen smaller than the CID causes a write of up to 31 bytes past the buffer end.\n\nIn CONFIG_USERSPACE builds the getsockopt syscall verifier (z_vrfy_zsock_getsockopt) bounce-buffers the user\u0027s optval into a kernel allocation of exactly optlen bytes (k_usermode_alloc_from_copy -\u003e z_thread_malloc), so an unprivileged user thread that passes a small optlen on a connected DTLS socket with Connection ID enabled induces a kernel-heap buffer overflow, with the overflowing content being the remote peer\u0027s CID.\n\nThe defect requires CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID, an established DTLS session with a negotiated peer CID, and (for the kernel-crossing case) CONFIG_USERSPACE. Introduced when the TLS_DTLS_CID option was added (v3.5.0).\n\nThe fix rejects callers whose optlen is below MBEDTLS_SSL_CID_OUT_LEN_MAX with -EINVAL."
    }
  ],
  "id": "CVE-2026-8718",
  "lastModified": "2026-08-26T16:59:23.267",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 5.8,
        "source": "vulnerabilities@zephyrproject.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-8718",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-12T18:49:17.354008Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-10T23:16:51.587",
  "references": [
    {
      "source": "vulnerabilities@zephyrproject.org",
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d"
    },
    {
      "source": "vulnerabilities@zephyrproject.org",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq"
    }
  ],
  "sourceIdentifier": "vulnerabilities@zephyrproject.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "vulnerabilities@zephyrproject.org",
      "type": "Secondary"
    }
  ]
}

CVE-2026-8718 (GCVE-0-2026-8718)

Vulnerability from cvelistv5 – Published: 2026-08-10 22:40 – Updated: 2026-08-12 18:49

Title

Out-of-bounds write in DTLS peer Connection ID getsockopt (`TLS_DTLS_PEER_CID_VALUE`) in Zephyr net sockets/TLS

Summary

Severity

8.4 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-12 18:49 UTC

CWE

CWE-787 - bounds

Assigner

zephyr mitre root

References

2 references

URL	Tags
https://github.com/zephyrproject-rtos/zephyr/comm…	patch
https://github.com/zephyrproject-rtos/zephyr/secu…

Impacted products

1 product

Vendor	Product	Version
zephyrproject	zephyr	Affected: 3.5.0 , < 4.4.1 (semver)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-8718",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-12T18:49:17.354008Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-12T18:49:59.886Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/net/lib/sockets/sockets_tls.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.1",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "tls_opt_dtls_peer_connection_id_value_get() in subsys/net/lib/sockets/sockets_tls.c, which handles getsockopt(SOL_TLS, TLS_DTLS_PEER_CID_VALUE), passed the caller-supplied optval directly to mbedtls_ssl_get_peer_cid() without verifying the buffer was at least MBEDTLS_SSL_CID_OUT_LEN_MAX (default 32) bytes. mbedtls_ssl_get_peer_cid() copies the peer-negotiated DTLS Connection ID (length 1..MBEDTLS_SSL_CID_OUT_LEN_MAX) into that buffer without a destination-size parameter, so a caller-supplied optlen smaller than the CID causes a write of up to 31 bytes past the buffer end.\n\nIn CONFIG_USERSPACE builds the getsockopt syscall verifier (z_vrfy_zsock_getsockopt) bounce-buffers the user\u0027s optval into a kernel allocation of exactly optlen bytes (k_usermode_alloc_from_copy -\u003e z_thread_malloc), so an unprivileged user thread that passes a small optlen on a connected DTLS socket with Connection ID enabled induces a kernel-heap buffer overflow, with the overflowing content being the remote peer\u0027s CID.\n\nThe defect requires CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID, an established DTLS session with a negotiated peer CID, and (for the kernel-crossing case) CONFIG_USERSPACE. Introduced when the TLS_DTLS_CID option was added (v3.5.0).\n\nThe fix rejects callers whose optlen is below MBEDTLS_SSL_CID_OUT_LEN_MAX with -EINVAL."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "bounds",
              "lang": "en",
              "type": "CWE"
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-10T22:40:26.836Z",
        "orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
        "shortName": "zephyr"
      },
      "references": [
        {
          "name": "Fix commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d"
        },
        {
          "name": "GHSA-p3r6-mx6c-33gq",
          "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq"
        }
      ],
      "title": "Out-of-bounds write in DTLS peer Connection ID getsockopt (`TLS_DTLS_PEER_CID_VALUE`) in Zephyr net sockets/TLS",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
    "assignerShortName": "zephyr",
    "cveId": "CVE-2026-8718",
    "datePublished": "2026-08-10T22:40:26.836Z",
    "dateReserved": "2026-05-15T21:27:25.564Z",
    "dateUpdated": "2026-08-12T18:49:59.886Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.