CVE-2026-40972: Spring Framework Spring Boot DevTools Remote Secret Vulnerability

HIGH
Advisory Identifier: GHSA-56v8-86gj-66jp
Share
CVSS 7.5
CWE-208
Published
Advisory Summary

CVE-2026-40972 is a HIGH (CVSS 7.5) spring boot devtools remote secret vulnerability (CWE-208: Observable Timing Discrepancy) affecting Spring Framework libraries in the Maven ecosystem. The issue involves spring boot devtools remote secret comparison is vulnerable to timing attacks. Remediation is available by upgrading affected packages to version 4.0.6, 3.5.14.

CVE-2026-40972 at a Glance

CVE Identifier CVE-2026-40972
GHSA Identifier GHSA-56v8-86gj-66jp
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-208: Observable Timing Discrepancy
Affected Product Spring Framework
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Adjacent (AV:A)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-40972

To remediate this vulnerability, upgrade all affected Spring Framework dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.springframework.boot:spring-boot-devtools fixed: 4.0.6 
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>4.0.6</version>
</dependency>
org.springframework.boot:spring-boot-devtools fixed: 3.5.14 
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>3.5.14</version>
</dependency>
org.springframework.boot:spring-boot-devtools fixed: Latest secure release 
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>Latest secure release</version>
</dependency>
org.springframework.boot:spring-boot-devtools fixed: Latest secure release 
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>Latest secure release</version>
</dependency>
org.springframework.boot:spring-boot-devtools fixed: Latest secure release 
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>Latest secure release</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.springframework.boot

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-40972, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.springframework.boot

Analyze the terminal output to locate any version of Spring Framework in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.0.6), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.springframework.boot command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-208: Observable Timing Discrepancy, where two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not. In Spring Framework, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

An attacker on the same network as the remote application may be able to utilize a timing attack to discover information about the remote secret. In extreme circumstances this could result in the attacker determining the secret and uploading changed classes, thereby achieving remote code execution in the remote application. Affected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14), 3.4.0–3.4.15 (fix 3.4.16), 3.3.0–3.3.18 (fix 3.3.19), 2.7.0–2.7.32 (fix 2.7.33); DevTools remote secret comparison. Versions that are no longer supported are also affected per vendor advisory.

CVE-2026-40972 Affected Spring Framework Versions

5 component(s)
Fixed Versions:
4.0.63.5.14
Product / Package Ecosystem Affected Versions Fixed Version
org.springframework.boot:spring-boot-devtools
maven/org.springframework.boot/spring-boot-devtools
Maven
≥ 4.0.0
< 4.0.6
4.0.6
org.springframework.boot:spring-boot-devtools
maven/org.springframework.boot/spring-boot-devtools
Maven
≥ 3.5.0
< 3.5.14
3.5.14
org.springframework.boot:spring-boot-devtools
maven/org.springframework.boot/spring-boot-devtools
Maven
≥ 3.4.0
≤ 3.4.15
org.springframework.boot:spring-boot-devtools
maven/org.springframework.boot/spring-boot-devtools
Maven
≥ 3.3.0
≤ 3.3.18
org.springframework.boot:spring-boot-devtools
maven/org.springframework.boot/spring-boot-devtools
Maven
≤ 2.7.32

References

NVD — CVE-2026-40972 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40972
Spring Framework Source Repository REPOSITORY
https://github.com/spring-projects/spring-boot
Spring Framework Security Information SECURITY
https://spring.io/security/cve-2026-40972

Frequently Asked Questions

What is CVE-2026-40972?
CVE-2026-40972 is a security vulnerability in Spring Framework involving Spring Boot DevTools remote secret comparison is vulnerable to timing attacks under CWE-208: Observable Timing Discrepancy.
Which Spring Framework versions are affected?
Affected versions include releases prior to 4.0.6, 3.5.14 across affected packages: org.springframework.boot:spring-boot-devtools.
What version fixes CVE-2026-40972?
Upgrading to 4.0.6, 3.5.14 (or the latest patched release for your respective branch) resolves the vulnerability.
Is spring-boot-devtools affected?
Yes, org.springframework.boot:spring-boot-devtools is affected in releases prior to 4.0.6, 3.5.14, Latest secure release. Upgrade your dependency to 4.0.6, 3.5.14, Latest secure release or later.
What is the CVSS score of CVE-2026-40972?
CVE-2026-40972 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-40972?
CVE-2026-40972 is classified under CWE-208: Observable Timing Discrepancy (Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.).
How can I check Maven dependencies for CVE-2026-40972?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.springframework.boot'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-56v8-86gj-66jp",
  "modified" : "2026-05-06T19:02:13Z",
  "published" : "2026-04-28T00:31:40Z",
  "aliases" : [ "CVE-2026-40972" ],
  "summary" : "Spring Boot DevTools remote secret comparison is vulnerable to timing attacks",
  "details" : "An attacker on the same network as the remote application may be able to utilize a timing attack to discover information about the remote secret. In extreme circumstances this could result in the attacker determining the secret and uploading changed classes, thereby achieving remote code execution in the remote application.\n\nAffected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14), 3.4.0–3.4.15 (fix 3.4.16), 3.3.0–3.3.18 (fix 3.3.19), 2.7.0–2.7.32 (fix 2.7.33); DevTools remote secret comparison. Versions that are no longer supported are also affected per vendor advisory.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.springframework.boot:spring-boot-devtools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.0.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.springframework.boot:spring-boot-devtools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.5.0"
      }, {
        "fixed" : "3.5.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.springframework.boot:spring-boot-devtools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.4.0"
      }, {
        "last_affected" : "3.4.15"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.springframework.boot:spring-boot-devtools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.3.0"
      }, {
        "last_affected" : "3.3.18"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.springframework.boot:spring-boot-devtools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.7.32"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40972"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/spring-projects/spring-boot"
  }, {
    "type" : "WEB",
    "url" : "https://spring.io/security/cve-2026-40972"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-208" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T19:02:13Z",
    "nvd_published_at" : "2026-04-28T00:16:24Z"
  }
}