esa ASN1SCC prior 4.7.0.1 XER Tokenizer asn1crt_encoding_xer.c NT stack-based overflow

Summaryinfo

A vulnerability categorized as critical has been discovered in esa ASN1SCC. This vulnerability affects the function NT of the file asn1crt/asn1crt_encoding_xer.c of the component XER Tokenizer. The manipulation results in stack-based overflow. This vulnerability is cataloged as CVE-2026-76077. The attack may be launched remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in esa ASN1SCC. Affected is the function NT of the file asn1crt/asn1crt_encoding_xer.c of the component XER Tokenizer. The manipulation with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-76077 since 08/18/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available.

Upgrading to version 4.7.0.1 eliminates this vulnerability.

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Vendor

• esa

Name

• ASN1SCC

Website

• Product: https://github.com/esa/asn1scc/

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