CVE-2026-76077

Description

A flaw was found in asn1scc. The XML Encoding Rules (XER) tokenizer does not properly enforce length bounds when copying tag data and fails to check buffer limits during input processing. A remote attacker could exploit this vulnerability by providing a crafted XER message, leading to stack memory corruption or out-of-bounds reads. Successful exploitation could permit arbitrary code execution, disclosure of adjacent memory, or a Denial of Service (DoS) condition by crashing or hanging the decoder.

Statement

Red Hat rates this vulnerability as Important rather than Critical because, although unauthenticated attackers could trigger stack corruption or service crashes remotely, successful exploitation requires an application to expose XML Encoding Rules (XER) decoding routines to unverified network data. Furthermore, asn1scc is not included in standard Red Hat Enterprise Linux environments, significantly limiting exposure across enterprise deployments. Risk remains confined to specialized workloads that ingest untrusted external ASN.1 XML streams.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Understanding the Weakness (CWE)

CWE-120

Integrity,Confidentiality,Availability

Technical Impact: Modify Memory; Execute Unauthorized Code or Commands

Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.

Availability

Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)

Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.

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