CVE-2026-76077 (GCVE-0-2026-76077)

Vulnerability from cvelistv5 – Published: 2026-11-05 16:49 – Updated: 2026-11-05 16:49
VLAI
Title
ASN1SCC: Stack buffer overflow and out-of-bounds read in XER tokenizer NT()
Summary
ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, the XER tokenizer NT() in asn1crt/asn1crt_encoding_xer.c, which is reached by all XER decode paths, copies tag characters into a fixed char Value[100] field without a length bound and reads input and lookahead bytes without checking the buffer count. A crafted XER message with an overlong tag can overwrite the tokenizer's stack frame, while a truncated tag or unterminated processing-instruction or comment sequence can read beyond the input and may cause a CPU spin. The flaws can disclose adjacent memory, corrupt stack data, crash or hang the decoder, and potentially permit code execution. This issue is fixed in version 4.7.0.1.
Severity
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
  • CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
  • CWE-125 - Out-of-bounds Read
  • CWE-787 - Out-of-bounds Write
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 8073 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
esa asn1scc Affected: < 4.7.0.1
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
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          "vendor": "esa",
          "versions": [
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            }
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          "lang": "en",
          "value": "ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, the XER tokenizer NT() in asn1crt/asn1crt_encoding_xer.c, which is reached by all XER decode paths, copies tag characters into a fixed char Value[100] field without a length bound and reads input and lookahead bytes without checking the buffer count. A crafted XER message with an overlong tag can overwrite the tokenizer\u0027s stack frame, while a truncated tag or unterminated processing-instruction or comment sequence can read beyond the input and may cause a CPU spin. The flaws can disclose adjacent memory, corrupt stack data, crash or hang the decoder, and potentially permit code execution. This issue is fixed in version 4.7.0.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-120",
              "description": "CWE-120: Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-125",
              "description": "CWE-125: Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787: Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-05T16:49:58.765Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/esa/asn1scc/security/advisories/GHSA-38q3-fg5h-wwf9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/esa/asn1scc/security/advisories/GHSA-38q3-fg5h-wwf9"
        },
        {
          "name": "https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9"
        },
        {
          "name": "https://github.com/esa/asn1scc/releases/tag/4.7.0.1",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/esa/asn1scc/releases/tag/4.7.0.1"
        }
      ],
      "source": {
        "advisory": "GHSA-38q3-fg5h-wwf9",
        "discovery": "UNKNOWN"
      },
      "title": "ASN1SCC: Stack buffer overflow and out-of-bounds read in XER tokenizer NT()"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-76077",
    "datePublished": "2026-11-05T16:49:58.765Z",
    "dateReserved": "2026-08-18T21:17:32.199Z",
    "dateUpdated": "2026-11-05T16:49:58.765Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-76077",
      "date": "2026-11-06",
      "epss": "0.00384",
      "percentile": "0.32709"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "asn1scc",
                "vendor": "esa",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 4.7.0.1"
                  }
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            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, the XER tokenizer NT() in asn1crt/asn1crt_encoding_xer.c, which is reached by all XER decode paths, copies tag characters into a fixed char Value[100] field without a length bound and reads input and lookahead bytes without checking the buffer count. A crafted XER message with an overlong tag can overwrite the tokenizer\u0027s stack frame, while a truncated tag or unterminated processing-instruction or comment sequence can read beyond the input and may cause a CPU spin. The flaws can disclose adjacent memory, corrupt stack data, crash or hang the decoder, and potentially permit code execution. This issue is fixed in version 4.7.0.1."
          }
        ],
        "id": "CVE-2026-76077",
        "lastModified": "2026-11-05T17:18:20.830",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
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              "impactScore": 5.9,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-11-05T17:18:20.830",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/esa/asn1scc/releases/tag/4.7.0.1"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/esa/asn1scc/security/advisories/GHSA-38q3-fg5h-wwf9"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-120"
              },
              {
                "lang": "en",
                "value": "CWE-125"
              },
              {
                "lang": "en",
                "value": "CWE-787"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
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    },
    "redhat_vex": {
      "current_release_date": "2026-11-06T19:23:01+00:00",
      "cve": "CVE-2026-76077",
      "id": "CVE-2026-76077",
      "initial_release_date": "2026-11-05T16:49:58.765000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "asn1scc: asn1scc: Arbitrary code execution via buffer overflow in XER tokenizer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76077.json",
      "version": "3"
    }
  }
}



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