CVE-2021-1104

Name: CVE-2021-1104
Creator: NVD / NIST
Published: 2021-08-13T16:15:07.153+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.66%

Last modified Jun 17, 2026

CVE-2021-1104 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 1.66% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.66%

73.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-908

Affected Software

Vendor	Product	Versions
Risc-V	Instruction Set Manual	All versions

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

Timeline

Published: Aug 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-1104?

How severe is CVE-2021-1104?

CVE-2021-1104 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.66% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1104?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-1104?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST