CVE-2026-5504 MEDIUM

CVE-2026-5504: PKCS7 CBC Padding Oracle — Plaintext Recovery

Vendor Wolfssl

Product wolfSSL

Weakness CWE-354

Published April 9, 2026

Last update April 14, 2026

View on NVD All CVEs

CVSS base score

6.3/10

Attack vector Network

Attack complexity High

Privileges required None

User interaction None

Confidentiality —

Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

A padding oracle exists in wolfSSL's PKCS7 CBC decryption that could allow an attacker to recover plaintext through repeated decryption queries with modified ciphertext. In previous versions of wolfSSL the interior padding bytes are not validated.

Key dates

02Disclosure timeline

April 9, 2026 CVE published

April 14, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-5504 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/354.html

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04Related CVE

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