CVE-2021-21677Network attack vector

Remote code execution via unfiltered Java deserialization

Published Aug 31, 2021 · Updated Aug 3, 2024

Unsafe deserialization in Jenkins Code Coverage API Plugin 1.4.0 and earlier allows remote attackers to execute code through a controlled agent. CompatibleObjectInputStream reads coverage-report objects with Java ObjectInputStream without Jenkins' default class filter. Control of a Jenkins agent process is required, and successful exploitation executes code on the Jenkins controller.

CVSS severity8.8
High
EPSS probability2.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in Jenkins Code Coverage API Plugin 1.4.0 and earlier allows remote attackers to execute code through a controlled agent. CompatibleObjectInputStream reads coverage-report objects with Java ObjectInputStream without Jenkins' default class filter. Control of a Jenkins agent process is required, and successful exploitation executes code on the Jenkins controller.

The record

CVE
CVE-2021-21677
Published
Aug 31, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
Code Coverage API Plugin
Classifications
CWE-502, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 31, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=unspecified <=1.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jenkins Project · Code Coverage API Pluginversion=unspecified <=1.4.0

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1210Exploitation of Remote Services

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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