Spring Security Advisories

CVE-2026-40972: DevTools remote secret comparison is vulnerable to timing attacks

HIGH | APRIL 23, 2026 | CVE-2026-40972

Description

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 Products and Versions

Spring Boot:

4.0.0 - 4.0.5
3.5.0 - 3.5.13
3.4.0 - 3.4.15
3.3.0 - 3.3.18
2.7.0 - 2.7.32

Versions that are no longer supported are also affected.

Mitigation

Users of affected versions should upgrade to the corresponding fixed version.

Affected version(s)	Fix version	Availability
4.0.x	4.0.6	OSS
3.5.x	3.5.14	OSS
3.4.x	3.4.16	Enterprise Support Only
3.3.x	3.3.19	Enterprise Support Only
2.7.x	2.7.33	Enterprise Support Only

No further mitigation steps are necessary.

References

https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H&version=3.1

History

2026-04-23: Initial vulnerability report published.

Reporting a vulnerability

To report a security vulnerability for a project within the Spring portfolio, see the Security Policy