CVE-2026-40986Network attack vector

Authenticated cross-site scripting via error response rendering

Published Jun 11, 2026 · Updated Jun 11, 2026

Cross-site scripting in Spring Web Flow 4.0.0, 3.0.0 through 3.0.1, and 2.5.0 through 2.5.1 allows remote authenticated users to run browser script. JavaScript RemotingHandler renders an Ajax error body as HTML without requiring a text/html Content-Type, allowing reflected attacker input to execute. Exposure requires spring-js-resources, Spring-Dojo.js for Ajax requests, an attacker-influenced server error, and user interaction.

CVSS severity4.8
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Spring Web Flow 4.0.0, 3.0.0 through 3.0.1, and 2.5.0 through 2.5.1 allows remote authenticated users to run browser script. JavaScript RemotingHandler renders an Ajax error body as HTML without requiring a text/html Content-Type, allowing reflected attacker input to execute. Exposure requires spring-js-resources, Spring-Dojo.js for Ajax requests, an attacker-influenced server error, and user interaction.

The record

CVE
CVE-2026-40986
Published
Jun 11, 2026
Updated
Jun 11, 2026
Vendor
Spring
Product
Spring Web Flow
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 11, 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?

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

  1. Affected versionversion=2.5.0 <2.5.2
  2. Affected versionversion=3.0.0 <3.0.2
  3. Affected versionversion=4.0.0 <4.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Spring · Spring Web Flowversion=2.5.0 <2.5.2; version=3.0.0 <3.0.2; version=4.0.0 <4.0.1

Published CVSS scores

4.8VMwareCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1059.007JavaScript/JScript

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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