Skip to main content
VulnerabilityPublished Updated

CVE-2026-40992: Spring Boot · Improper Certificate Validation

Affects Spring BootSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 5.0 Medium · fixed in 4.0.6.1 : update Spring Boot when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
5.0Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.0.6.1, 3.5.14.1, 3.4.17
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade Spring Boot to 4.0.6.1, 3.5.14.1 or 3.4.17.

Affected software

ProductAffectedFixed in
SpringSpring BootAffected
  • >=4.0.0 <4.0.6.1
Fixed in
  • 4.0.6.1
SpringSpring BootAffected
  • >=3.5.0 <3.5.14.1
Fixed in
  • 3.5.14.1
SpringSpring BootAffected
  • >=3.4.0 <3.4.17
Fixed in
  • 3.4.17
Mavenorg.springframework.boot/spring-bootpkg:maven/org.springframework.boot/spring-bootOther threatsAffected
  • =3.4.0 <=3.4.16
  • =3.5.0 <=3.5.14
  • =4.0.0 <=4.0.6
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability, applications should explicitly enable hostname verification by setting the JavaMail property spring.mail.properties.mail.smtp.ssl.checkserveridentity=true in their configuration. This setting disables the vulnerability by enforcing proper certificate validation. Monitor the vendor advisory for any future official fixes or updates.

Description

Spring Boot's Mail auto-configuration does not enable hostname verification. Applications that set the relevant JavaMail property, such as spring.mail.properties.mail.smtp.ssl.checkserveridentity=true, are not affected. Affected versions: Spring Boot 4.0.0 through 4.0.6; 3.5.0 through 3.5.14; 3.4.0 through 3.4.16.

References

Community reviews

Loading reviews…