Timing Attack Affecting org.springframework.boot:spring-boot-devtools package, versions [,3.5.14)[4.0.0-M1,4.0.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published24 Apr 2026
- disclosed23 Apr 2026
- creditUnknown
Introduced: 23 Apr 2026
CVE-2026-40972 (opens in a new tab)How to fix?
Upgrade org.springframework.boot:spring-boot-devtools to version 3.5.14, 4.0.6 or higher.
Overview
Affected versions of this package are vulnerable to Timing Attack in DevTool due to comparing the user-provided "remote secret" against the actual secret using standard string comparison logic (like String.equals() or ==). Standard string comparisons are not constant-time. They evaluate character by character and exit immediately (return false) as soon as they find the first mismatch. Because the comparison stops early upon a mismatch, it takes slightly longer to reject a guess that gets the first few characters correct than a guess that is completely wrong. An attacker on the same network can measure these microsecond differences to deduce the secret character by character.