CVE-2026-27099Network attack vector

Stored XSS via unescaped offline description

Published Feb 18, 2026 · Updated Feb 18, 2026

Stored XSS in Jenkins 2.483 through 2.550 and LTS 2.492.1 through 2.541.1 allows remote authenticated users to execute browser scripts. OfflineCause.UserCause.getMessage returns the user-provided “Mark temporarily offline” description as trusted HTML without escaping it before the node page renders it. Agent/Configure or Agent/Disconnect permission is required to store the payload, and another user must view the affected page for script execution in that user's browser.

CVSS severity8.0
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Jenkins 2.483 through 2.550 and LTS 2.492.1 through 2.541.1 allows remote authenticated users to execute browser scripts. OfflineCause.UserCause.getMessage returns the user-provided “Mark temporarily offline” description as trusted HTML without escaping it before the node page renders it. Agent/Configure or Agent/Disconnect permission is required to store the payload, and another user must view the affected page for script execution in that user's browser.

The record

CVE
CVE-2026-27099
Published
Feb 18, 2026
Updated
Feb 18, 2026
Vendor
Jenkins Project
Product
Jenkins
Classifications
CWE-79
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 2026Record 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 versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jenkins Project · JenkinsAffected versions are unavailable in this record.

Published CVSS scores

8.0CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/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 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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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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