---
id: CVE-2026-76077
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…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-120
  - CWE-125
  - CWE-787
vendor: esa
product: asn1scc
affected:
  - asn1scc < 4.7.0.1
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T16:49:58.765Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-76077'
references:
  - url: 'https://github.com/esa/asn1scc/security/advisories/GHSA-38q3-fg5h-wwf9'
    label: 'https://github.com/esa/asn1scc/security/advisories/GHSA-38q3-fg5h-wwf9'
  - url: >-
      https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9
    label: >-
      https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9
  - url: 'https://github.com/esa/asn1scc/releases/tag/4.7.0.1'
    label: 'https://github.com/esa/asn1scc/releases/tag/4.7.0.1'
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.408Z'
---

## Overview

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.

## Affected

- `asn1scc < 4.7.0.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.