wolfSSL up to 5.9.0 PKCS7 CBC Decryption integrity check

CVSS Meta Temp Score
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CTI Interest Score
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3.6$0-$5k0.56-

Summaryinfo

A vulnerability labeled as problematic has been found in wolfSSL up to 5.9.0. This affects an unknown part of the component PKCS7 CBC Decryption. The manipulation results in integrity check. This vulnerability was named CVE-2026-5504. The attack may be performed from remote. There is no available exploit. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability classified as problematic has been found in wolfSSL up to 5.9.0. Affected is an unknown part of the component PKCS7 CBC Decryption. The manipulation with an unknown input leads to a integrity check vulnerability. CWE is classifying the issue as CWE-354. The product does not validate or incorrectly validates the integrity check values or "checksums" of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission. This is going to have an impact on confidentiality. CVE summarizes:

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.

The weakness was presented by Sunwoo Lee. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-5504 since 04/03/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 305898 (Linux Distros Unpatched Vulnerability : CVE-2026-5504), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (305898). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.6

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integrity check
CWE: CWE-354 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 305898
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-5504

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: github.com

Timelineinfo

04/03/2026 CVE reserved
04/10/2026 +7 days Advisory disclosed
04/10/2026 +0 days VulDB entry created
04/11/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Researcher: Sunwoo Lee
Status: Confirmed

CVE: CVE-2026-5504 (🔒)
GCVE (CVE): GCVE-0-2026-5504
GCVE (VulDB): GCVE-100-356688

Entryinfo

Created: 04/10/2026 06:10
Updated: 04/11/2026 01:12
Changes: 04/10/2026 06:10 (66), 04/11/2026 01:12 (2)
Complete: 🔍
Cache ID: 216:176:103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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