{"id":"CVE-2026-102758","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-102758","generatedAt":"2026-10-28T01:53:25.751Z","title":"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.","description":"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.\n\n\n\nThe 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.\n\n\n\ncode:\n\n\n\nnx_secure/src/nx_secure_x509_asn1_tlv_block_parse.c\n\n\n\n```\n\n\n\nUINT _nx_secure_x509_asn1_tlv_block_parse(const UCHAR *buffer, ULONG *buffer_length, USHORT *tlv_type,\n\n                                          USHORT *tlv_tag_class, ULONG *tlv_length,\n                                          const UCHAR **tlv_data, ULONG *header_length)\n\n\n{\n\n\n\nUINT   current_index;\n\n\n\nUSHORT current_tag;\n\n\n\nULONG  length;\n\n\n\nULONG  length_bytes;\n\n    current_index = 0;\n    current_tag = buffer[current_index];      /* <-- read before the bounds check */\n    if (*buffer_length < 1)\n    {\n        return(NX_SECURE_X509_ASN1_LENGTH_TOO_LONG);\n    }\n\n\n```\n\n\n\nThe 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.","published":"2026-09-29T18:17:13.000Z","lastModified":"2026-09-30T21:17:05.000Z","status":"Awaiting Analysis","sourceIdentifier":"emo@eclipse.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-126"],"affected":[],"epss":{"score":0.00173,"percentile":0.06711,"date":"2026-10-26","history":[{"date":"2026-09-30","score":0.00093,"percentile":0.00512}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"scored","label":"Newly scored","at":"2026-09-30T23:15:17.000Z","detail":{"from":null,"score":"7.5","severity":"HIGH","fromSeverity":null},"summary":"Now scored CVSS 7.5 HIGH."},{"kind":"new","label":"New CVE","at":"2026-09-29T18:17:13.000Z","detail":{"score":null,"severity":null,"publishedAt":"2026-09-29T18:17:13.047Z"},"summary":"New CVE, high severity (CVSS 7.5)."}],"references":[{"url":"https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-f95g-xc4w-mrcr","source":"emo@eclipse.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-102758","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}