PatchSiren cyber security CVE debrief

CVE-2026-40996 Spring CVE debrief

CVE-2026-40996 is a vulnerability in Spring Web Services that affects versions 5.0.0 through 5.0.1, 4.1.0 through 4.1.3, 4.0.0 through 4.0.18, and 3.1.0 through 3.1.8. The vulnerability arises from the Wss4jSecurityInterceptor's default setting of allowRSA15KeyTransportAlgorithm to true, which overrides Apache WSS4J's safer default. This allows for the acceptance of RSA PKCS#1 v1.5 (rsa-1_5) encrypted key material for inbound WS-Security decryption, unless explicitly reconfigured by operators.

Vendor: Spring
Product: Spring Web Services
CVSS: MEDIUM 4.8
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-11
Original CVE updated: 2026-06-11
Advisory published: 2026-06-11
Advisory updated: 2026-06-11

Who should care

Users of affected Spring Web Services versions should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability has a CVSS score of 4.8 and is classified as MEDIUM severity. It can be exploited through network-based attacks with high complexity and no user interaction.

Defensive priority

MEDIUM

Recommended defensive actions

Upgrade to a non-affected version of Spring Web Services.
Reconfigure the allowRSA15KeyTransportAlgorithm flag to false if upgrading is not feasible.

Evidence notes

The CVE record and NVD detail can be found at [cve-org] and [nvd], respectively. Additional information is available at [ref-4].

Official resources

CVE-2026-40996 was published on 2026-06-11T07:16:27.550Z and modified on 2026-06-11T15:21:30.653Z.