CVE-2021-35588Network attack vector

JVM crash via invalid inner-class indexes

Published Oct 20, 2021 · Updated Aug 4, 2024

Improper input validation in HotSpot in Oracle Java SE 7u311 and 8u301 allows remote attackers to crash the JVM via a crafted class file. ClassFileParser incompletely validates inner-class index values while loading the attacker-supplied class. Exploitation requires untrusted code or hostile data supplied to HotSpot APIs, and client-side delivery requires user interaction.

CVSS severity3.1
Low
EPSS probability3.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in HotSpot in Oracle Java SE 7u311 and 8u301 allows remote attackers to crash the JVM via a crafted class file. ClassFileParser incompletely validates inner-class index values while loading the attacker-supplied class. Exploitation requires untrusted code or hostile data supplied to HotSpot APIs, and client-side delivery requires user interaction.

The record

CVE
CVE-2021-35588
Published
Oct 20, 2021
Updated
Aug 4, 2024
Vendor
Oracle Corporation
Product
Java Platform, Standard Edition (Java SE)
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 20, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Java SE:7u311
  2. Affected versionversion=Java SE:8u301
  3. Affected versionversion=Oracle GraalVM Enterprise Edition:20.3.3
  4. Affected versionversion=Oracle GraalVM Enterprise Edition:21.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Java Platform, Standard Edition (Java SE)version=Java SE:7u311; version=Java SE:8u301; version=Oracle GraalVM Enterprise Edition:20.3.3; version=Oracle GraalVM Enterprise Edition:21.2.0

Published CVSS scores

3.1Oracle CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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