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CVE-2026-5504

PKCS7 CBC Padding Oracle — Plaintext Recovery

Published: Apr 9, 2026Updated: Apr 29, 2026 Sources: CVE List NVDCWE-354
NVD MITRE
5.3CVSSMEDIUM
EPSS Score
0.1%
Top 98.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-354

Affected Products

wolfSSLwolfSSL
LibraryLibrary
OSS Libraries / generic-library
wolfsslwolfssl
LibraryLibrary
OSS Libraries / generic-library
wolfssloss-projectOSS Librariesaka wolfmqtt, wolfssh, wolfssl

Exploitability

Official Patch Available

References

https://github.com/wolfSSL/wolfssl/pull/10088
github.com

Timeline

Published
Apr 9, 2026
Last Updated
Apr 29, 2026

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