CVE-2021-2369Network attack vector

Data modification via duplicate-manifest JAR signature bypass

Published Jul 20, 2021 · Updated Sep 26, 2024

Improper JAR signature verification in Oracle Java SE and GraalVM Enterprise Edition allows remote attackers to alter accessible data. The Library component can return a successful signature result for a JAR containing multiple MANIFEST.MF files, letting tampered signed content pass verification. Affected releases are Java SE 7u301, 8u291, 11.0.11, and 16.0.1 and GraalVM 20.3.2 and 21.1.0; exploitation requires another person to run untrusted code in a sandboxed Java Web Start or applet client, while trusted-code server deployments are unaffected.

CVSS severity4.3
Medium
EPSS probability3.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper JAR signature verification in Oracle Java SE and GraalVM Enterprise Edition allows remote attackers to alter accessible data. The Library component can return a successful signature result for a JAR containing multiple MANIFEST.MF files, letting tampered signed content pass verification. Affected releases are Java SE 7u301, 8u291, 11.0.11, and 16.0.1 and GraalVM 20.3.2 and 21.1.0; exploitation requires another person to run untrusted code in a sandboxed Java Web Start or applet client, while trusted-code server deployments are unaffected.

The record

CVE
CVE-2021-2369
Published
Jul 20, 2021
Updated
Sep 26, 2024
Vendor
Oracle Corporation
Product
Java Platform, Standard Edition (Java SE)
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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:11.0.11
  2. Affected versionversion=Java SE:16.0.1
  3. Affected versionversion=Java SE:7u301
  4. Affected versionversion=Java SE:8u291
  5. Affected versionversion=Oracle GraalVM Enterprise Edition:20.3.2
  6. Affected versionversion=Oracle GraalVM Enterprise Edition:21.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Java Platform, Standard Edition (Java SE)version=Java SE:11.0.11; version=Java SE:16.0.1; version=Java SE:7u301; version=Java SE:8u291; version=Oracle GraalVM Enterprise Edition:20.3.2; version=Oracle GraalVM Enterprise Edition:21.1.0

Published CVSS scores

4.3Oracle CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

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

Weakness, pattern, technique

T1204.002User Execution: Malicious File

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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