CVE-2020-5408: Dictionary attack with Spring Security queryable text encryptor

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-05-14 · updated 2026-06-17
Weakness: CWE-329

Description

Spring Security versions 5.3.x prior to 5.3.2, 5.2.x prior to 5.2.4, 5.1.x prior to 5.1.10, 5.0.x prior to 5.0.16 and 4.2.x prior to 4.2.16 use a fixed null initialization vector with CBC Mode in the implementation of the queryable text encryptor. A malicious user with access to the data that has been encrypted using such an encryptor may be able to derive the unencrypted values using a dictionary attack.

Affected products

Spring by VMware Spring Security: from 5.2.0 before 5.2.4; from 5.3.0 before 5.3.2 — fixed in 5.2.4, 5.3.2
Spring Security: from 4.2.0 before 4.2.16; from 5.0.0 before 5.0.16; from 5.1.0 before 5.1.10 — fixed in 4.2.16, 5.0.16, 5.1.10
Spring by VMware Spring Security: from 4.2 before 4.2.16; from 5.0 before 5.0.16; from 5.1 before 5.1.10; from 5.2 before 5.2.4; from 5.3 before 5.3.2 — fixed in 4.2.16, 5.0.16, 5.1.10, 5.2.4, 5.3.2

How to fix

Upgrade to a fixed version: Spring by VMware Spring Security 5.2.4, 5.3.2; Spring Security 4.2.16, 5.0.16, 5.1.10; Spring by VMware Spring Security 4.2.16, 5.0.16, 5.1.10, 5.2.4. Check the vendor advisory for mitigations.

References

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