Security advisory

{
  "id": "c5db883c585b837e7c4af2f78bff9bd91e304000a87079d6ebc38867b553e772",
  "url": "https://osv.dev/vulnerability/CVE-2026-102758",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-102758",
    "summary": "The `_nx_secure_x509_asn1_tlv_block_parse()` function parses ASN.1 TLV (tag-length-value) blocks out of DER-encoded data. It is the primitive underneath all X.509 certificate parsing in NetX Secure, and therefore runs on certificates supplied by a remote peer during the TLS handshake. The function reads the one-byte ASN.1 tag from the caller's buffer *before* checking that the buffer holds at least one byte. When a caller passes a remaining length of zero, the guard correctly returns `NX_SECURE_X509_ASN1_LENGTH_TOO_LONG`, but the read has already happened one byte past the end of the buffer. code: nx_secure/src/nx_secure_x509_asn1_tlv_block_parse.c ``` UINT _nx_secure_x509_asn1_tlv_block_parse(const UCHAR *buffer, ULONG *buffer_length, USHORT *tlv_type, USHORT *tlv_tag_class, ULONG *tlv_length, const UCHAR **tlv_data, ULONG *header_length) { UINT current_index; USHORT current_tag; ULONG length; ULONG length_bytes; current_index = 0; current_tag = buffer[current_index]; /* <-- read before the bounds check */ if (*buffer_length < 1) { return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG); } ``` The remainder of the function is correctly ordered. The multi-byte length path is guarded by `length_bytes > 4 || length_bytes > *buffer_length` before its read loop, the decoded value is checked against `length > *buffer_length`, and the second single-byte length read follows its own `*buffer_length < 1` guard. The tag read is the only load placed ahead of its check.",
    "evidence": "osv:CVE-2026-102758",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-102758",
      "aliases": [
        "CVE-2026-102758",
        "GHSA-f95g-xc4w-mrcr"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/eclipse-threadx/netxduo",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "1a0e9e43a03e37ddecfb6b49e9b078d6e1803d05"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "6.5.1.202602"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v6.4.1_rel",
            "v6.5.1.202602_rel",
            "v6.5.0.202601_rel",
            "v6.4.5.202504_rel",
            "v6.4.4.202503a",
            "v.6.4.4.202503_rel",
            "v6.4.3_rel",
            "v6.4.2_rel",
            "v6.4.0_rel",
            "v6.3.0_rel",
            "v6.2.1_rel",
            "v6.2.0_rel",
            "v6.1.12_rel",
            "v6.1.11_rel",
            "v6.1.10_rel",
            "v6.1.9_rel",
            "v6.1.8_rel",
            "v6.1.7_rel",
            "v6.1.6_rel",
            "v6.1.5_rel",
            "v6.1.4_rel",
            "v6.1.3_rel",
            "v6.1.2_rel",
            "v6.1_rel",
            "v6.0.2_rel",
            "v6.0.1_rel",
            "v6.0_rel"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102758.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.672192915Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102758.json",
        "https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-f95g-xc4w-mrcr",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-102758"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-126"
        ],
        "cna_assigner": "eclipse",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102758.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-102758",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506153,
  "published_at": "2026-09-29T17:26:44.424+00:00"
}