CVE-2026-75806

Full vulnerability record from the local CVENow database.

Description

Issue summary: An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. Impact summary: An attacker who can send a datagram that is routed to an existing DTLS 1.2 association can tear that association down without knowing any key material. This is a Denial of Service limited to the targeted association. There is no memory safety or confidentiality impact. CWE: CWE-1284: Improper Validation of Specified Quantity in Input Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher suite carries an explicit IV followed by the ciphertext and an authentication tag. When decrypting such a record the record layer passed the record length to the cipher implementation before checking that the record was long enough to contain the explicit IV and the tag. For a record shorter than that overhead the cipher implementation rejected the impossible length, and the record layer treated this as an internal failure and raised a fatal internal_error alert instead of treating the record as one that failed authentication. In TLS 1.2 the same record causes a fatal internal_error alert instead of the expected bad_record_mac alert. Since any undecryptable record already terminates a TLS connection, this is a protocol conformance issue rather than a security issue in TLS. The fix validates the record length against the explicit IV and tag length before any AEAD processing, so that TLS reports bad_record_mac and DTLS silently discards the record. FIPS impact: no The affected code is outside the FIPS module boundary.

Severity

MEDIUM

CVSS score

5.3 (v3.1)

Vulnerability status

Modified

Source identifier

[email protected]

Published

2026-09-29 16:17:11.217000

Last modified

2026-11-10 13:19:39.453000

View original CVE JSON

{
  "id": "CVE-2026-75806",
  "sourceIdentifier": "[email protected]",
  "published": "2026-09-29T16:17:11.217",
  "lastModified": "2026-11-10T13:19:39.453",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue summary: An established DTLS 1.2 association using an AEAD cipher suite\ncan be terminated by a single unauthenticated datagram whose encrypted\nfragment is shorter than the mandatory explicit IV and authentication tag\noverhead.\n\nImpact summary: An attacker who can send a datagram that is routed to an\nexisting DTLS 1.2 association can tear that association down without knowing\nany key material. This is a Denial of Service limited to the targeted\nassociation. There is no memory safety or confidentiality impact.\n\nCWE: CWE-1284: Improper Validation of Specified Quantity in Input\n\nDescription: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher\nsuite carries an explicit IV followed by the ciphertext and an authentication\ntag. When decrypting such a record the record layer passed the record length to\nthe cipher implementation before checking that the record was long enough to\ncontain the explicit IV and the tag. For a record shorter than that overhead the\ncipher implementation rejected the impossible length, and the record layer\ntreated this as an internal failure and raised a fatal internal_error alert\ninstead of treating the record as one that failed authentication.\n\nIn TLS 1.2 the same record causes a fatal internal_error alert instead of the\nexpected bad_record_mac alert. Since any undecryptable record already\nterminates a TLS connection, this is a protocol conformance issue rather than\na security issue in TLS.\n\nThe fix validates the record length against the explicit IV and tag length\nbefore any AEAD processing, so that TLS reports bad_record_mac and DTLS\nsilently discards the record.\n\nFIPS impact: no\nThe affected code is outside the FIPS module boundary."
    }
  ],
  "affected": [
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          "vendor": "Siemens",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)",
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  "metrics": {
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          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW"
        },
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      }
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    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
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          "id": "CVE-2026-75806",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
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              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
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        }
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  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
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          "value": "CWE-1284"
        }
      ]
    }
  ],
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          "negate": false,
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}