The Apache Tomcat EncryptInterceptor is vulnerable to a padding oracle when enabled by default. By submitting specially crafted ciphertext and observing decryption or error responses, an attacker can recover the original plaintext of encrypted data. This breach can expose confidential configuration details or session information stored by a web application, resulting in a confidentiality compromise. The weakness is associated with CWE-1240, CWE-209, and CWE-642.

Apache Tomcat versions 11.0.0-M1 through 11.0.18, 10.0.0-M1 through 10.1.52, 9.0.13 through 9.0.115, 8.5.38 through 8.5.100, and 7.0.100 through 7.0.109 are affected. Administrators should upgrade to 11.0.19, 10.1.53, or 9.0.116 where the issue is fixed. Versions in the 8.5.x and 7.x lines have no currently released fix; disabling the interceptor or awaiting a newer release is recommended.

The CVSS base score of 7.5 classifies the vulnerability as high severity, and the EPSS score of 6% indicates a moderate probability of real‑world exploitation. The vulnerability is not listed in the CISA KEV catalog. Based on the description, it is inferred that the likely attack vector is remote HTTP access to a Tomcat instance that has the EncryptInterceptor enabled by default; by transmitting crafted ciphertext and monitoring error responses or timing, an attacker can systematically recover plaintext. Successful exploitation would give an attacker the ability to read sensitive information encrypted by Tomcat.