CVE-2021-41862Public exploitNetwork attack vector

Arbitrary code execution via BCEL class loading

Published Oct 1, 2021 · Updated Aug 4, 2024

Expression injection in AviatorScript 5.2.1 through 5.2.7 allows context-dependent attackers to execute arbitrary code via crafted expressions. The evaluator permits expressions to instantiate a BCEL ClassLoader with attacker-supplied encoded bytecode and invoke a public static method from the loaded class. A consuming application must submit attacker-controlled text for evaluation; successful execution runs commands with the privileges of the host JVM process.

CVSS severity9.8
Critical
EPSS probability1.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Expression injection in AviatorScript 5.2.1 through 5.2.7 allows context-dependent attackers to execute arbitrary code via crafted expressions. The evaluator permits expressions to instantiate a BCEL ClassLoader with attacker-supplied encoded bytecode and invoke a public static method from the loaded class. A consuming application must submit attacker-controlled text for evaluation; successful execution runs commands with the privileges of the host JVM process.

The record

CVE
CVE-2021-41862
Published
Oct 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 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 exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1059Command and Scripting Interpreter

Public exploit references

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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