CVE-2020-36404

Application crash via invalid RIP register expressions

Published Jul 1, 2021 · Updated Aug 4, 2024

Invalid free in Keystone Engine 0.9.2 allows attackers to crash applications that process crafted assembly text through its x86 assembler. X86AsmParser accepts RIP as an index register or combines a RIP base with an index instead of rejecting the invalid memory expression, and fragment destruction later reaches the invalid free. Exploitation requires a consuming application to pass attacker-controlled x86 assembly text into the library; a crash is demonstrated, but code execution is not publicly demonstrated.

CVSS severity7.8
High
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid free in Keystone Engine 0.9.2 allows attackers to crash applications that process crafted assembly text through its x86 assembler. X86AsmParser accepts RIP as an index register or combines a RIP base with an index instead of rejecting the invalid memory expression, and fragment destruction later reaches the invalid free. Exploitation requires a consuming application to pass attacker-controlled x86 assembly text into the library; a crash is demonstrated, but code execution is not publicly demonstrated.

The record

CVE
CVE-2020-36404
Published
Jul 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-763, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-763Release of Invalid Pointer or Reference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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