# CVE-2026-75614: ASN1SCC: Out-of-bounds write in BitStream_DecodeConstraintWholeNumber (uPER/ACN)

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

ASN1SCC is an open source ASN.1 compiler for embedded systems. Prior to 4.7.0.1, BitStream_DecodeConstraintWholeNumber in asn1crt/asn1crt_encoding.c reads enough bits for a constrained integer but does not reject values above the declared range when the encoded range is not a power of two. Generated uPER and ACN decoders for variable-size SEQUENCE OF, OCTET STRING, BIT STRING, and string values use the invalid result as a loop or copy length, so a crafted over-range size field can write beyond a destination buffer. Decoding untrusted affected data can corrupt heap or stack memory, cause a crash, or potentially permit code execution. This issue is fixed in version 4.7.0.1.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- esa / asn1scc: < 4.7.0.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 8.1 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-129, CWE-787

## Exploit evidence

- exploit: https://github.com/esa/asn1scc/security/advisories/GHSA-825c-7h77-2jjq (ADP: CISA-ADP)

## References

- https://github.com/esa/asn1scc/security/advisories/GHSA-825c-7h77-2jjq (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/esa/asn1scc/releases/tag/4.7.0.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/esa/asn1scc/security/advisories/GHSA-825c-7h77-2jjq (ADP: CISA-ADP; exploit)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-75614; retrieved 2026-11-05; source updated 2026-11-05

Revision: 2985b48e729b45157bd0d74f2eb8db6dc34433b6d1df42991276ad79b87ad95e

Canonical: https://y2.dev/cve/CVE-2026-75614

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