Vulnerability · Published Nov 5, 2026 · Assigned by GitHub_M

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

High 8.1

In plain English

A high-severity out-of-bounds write in asn1scc from esa. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.6%top 52.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
esa	asn1scc	< 4.7.0.1

Weakness: CWE-129, CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/esa/asn1scc/security/advisories/GHSA-825c-7h77-2jjq x_refsource_CONFIRM
https://github.com/esa/asn1scc/commit/fe6ab763bc60d8a2def4104c15414809b45fffd9 x_refsource_MISC
https://github.com/esa/asn1scc/releases/tag/4.7.0.1 x_refsource_MISC