CVE-2021-1104: The RISC-V Instruction Set Manual contains a documented ambiguity for the Machine Trap Vector Base Address (MT

This week

CRITICAL 9.8REMOTEMITIGATE

CVE-2021-1104 is a critical-severity flaw (CVSS 9.8) affecting instruction set manual. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-908
Published	2021-08-13
Last modified	2026-06-17

Publisher (CNA): NVIDIA Corporation · Vendor: risc-v

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-13 16:15 UTCPublished CVE record published
2026-06-17 03:30 UTCUpdated Record last modified

risc-v instruction set manual MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy instruction-set-manual || rpm -q instruction-set-manual || instruction-set-manual --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-1104?

instruction set manual: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-1104 being exploited?

CVE-2021-1104 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-1104 affect?

CVE-2021-1104 affects instruction set manual. Severity is critical (CVSS 9.8). 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

How urgent is CVE-2021-1104?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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